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Elenco dei seminari tenuti al DIMA precedentemente

17 settembre 2019 - Aula 705 - Seminario di Tatiana Bubba - Malga Seminar Analysis and Learning (Professor Matteo Santacesaria)
24 luglio 2019 - Aula 714 - Seminario di Derived crital locus of a linear guage theory (Professor Marco Benini)
23 luglio 2019 - Aula 704 - Seminario di Seminario Giovanni Canepa (Professor Marco Benini)
17 luglio 2019 - Aula 713 - Seminario di Algebra e Geometria (M. Varbaro)

ore 14:00 - Paolo Mantero (University of Arkansas)

"Singularities and canonical modules of Rees-like algebras"

Abstract: Recently, Peeva and McCullough introduced Rees-like algebras to construct non-normal varieties which are counterexamples to Eisenbud-Goto regularity conjecture. In this talk we focus on the nature of the geometry of these varieties. We study their singular locus,
and characterize when they are weakly normal, seminormal and F-split. Finally, we exhibit a finite free resolution of the canonical module of a Rees-like algebra which has a surprising self-dual structure. This talk is based on a joint work with J. McCullough and L.E. Miller.

ore 15:00 - Giulio Caviglia (Purdue University)

"Sequentially Cohen Macaulay modules and graded local cohomology tables"

Abstract: We consider, along the lines of Boij-Soderberg theory, the problem of writing local cohomology tables as finite sums, with positive rational coefficients, of tables from an explicit list. We show how this can be easily done for sequentially Cohen Macaulay modules. We then extend previous work by De Stefani and Smirnov by considering modules with large E-depth, i.e. a weaker condition than being sequentially Cohen Macaulay. Finally we show how the E- depth can be computed using partial generic initial ideals. This is a joint work with Alessandro De Stefani
16 luglio 2019 - Aula 713 - Seminario (M. Benini)

ore 14:00-16:00 - Prof. Richard J. Szabo

10 luglio 2019 - Aula 713 - Seminario di Algebra e Geometria

ore 15:00 - Kumari Saloni (Chennai Mathematical Institute)

"Bounding Hilbert coecients"

Abstract: Let R be a local ring with maximal ideal m. Although by de nition, the Hilbert-Samuel polynomial and the Hilbert coecients of an m-primary ideal carry asymptotic information about the powers of the ideal, they indeed encode a lot of properties of R and of the associated graded ring of the ideal. The Hilbert coecients enjoy a lot of interesting relationships among themselves and the respective boundary conditions force good depth properties. For instance, vanishing of the rst coecient e1(Q), for a parameter ideal Q, plays an important role in the characterization of Cohen-Macaulay rings. The higher coecients are dicult to work with. In this talk, we discuss certain bounds on the Hilbert coecients of parameter ideals in Noetherian local ring and their boundary conditions. In particular, we will discuss the non-positivity of e3(Q) using local cohomology modules.
10 luglio 2019 - Aula 714 - Seminario di Categorical equivalence between factorization algebras and algebraic quantum field theories. (Professor Marco Benini)
8 luglio 2019 - Aula 704 - Seminario (Carbonaro)

ore 15:00 -

"Lusin-type approximation of Sobolev by Lipschitz functions in Gaussian spaces"

Abstract:
8 luglio 2019 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-15:00 - Josh Pollitz (University of Nebraska)

"Derived Categories in commutative algebra"

Abstract: Let R be a commutative noetherian ring. It is well known that R is regular if and only if every complex with finitely generated homology is a perfect complex. The goal of this talk is to explain how one can characterize whether R is locally a complete intersection in terms of how each complex with finitely generated homology relates to the perfect complexes. Namely, R is locally a complete intersection if and only if each nontrivial complex with finitely generated homology can build a nontrivial perfect complex in the derived category using finitely many cones and retracts. This characterization gives a completely triangulated category characterization of locally complete intersection rings. In this talk, we will introduce a theory of support varieties and discuss how they can be applied to yield this characterization.
4 luglio 2019 - Aula 714 - Seminario (Rosolini)

"Relating the effective topos to HoTT"

3 luglio 2019 - Aula 713 - Seminario di Algebra&Geometry seminar (Prof. Matteo Penegini)

Pagina web

ore 14:00-16:00 - Prof. Robert Laterveer (University of Strasburg) - laterv@math.unistra.fr

"On the Chow ring of double EPW sextics"

Abstract: Double EPW sextics form a 20-dimensional family of hyperkaehler fourfolds deformation equivalent to the Hilbert square of a K3 surface.
In this talk, I will present several results concerning their Chow ring - some progress towards the Beauville-Voisin conjecture,
some progress towards the generalized Franchetta conjecture, and some new results concerning the action of the anti-symplectic involution on the Chow group of zero-cycles. This is work in progress joint with Charles Vial.
27 giugno 2019 - Aula 716 - Seminario di Working seminar Degenerations (Professoressa Chiara Camere)
21 giugno 2019 - Aula 705 - Seminario di Machine Learning (Alberti)

ore 14:30 - Swaraj Paul (Indian Institute of Technology Indore)

"Resolution of Sobolev wavefront set and sparse representation of singular integral operator using shearlets
"

Abstract: The main ingredients of time-frequency analysis, such as wavelets and Gabor frames have been successfully used for the representation of most of the classes of pseudo-differential operators, singular integral operators (SIOs). The location and the geometry of the set of singularities of a distribution can be obtained by using continuous transform. The continuous transform of a distribution is related to the microlocal analysis. Microlocal analysis can be employed to study how singularities propagate under certain classes of operators, i.e., Fourier integral operators, pseudo-differential operators as well as many integral operators arising in integral geometry. Wavefront set of a distribution is an essential concept in the microlocal analysis. The microlocal analysis is perhaps useful in inverse problems, where the goal is to recover the wavefront set of a function or distribution from the solution of operator equation. In this talk, our aim is to characterize sobolev wavefront set using shearlets, and its connection with Holder regularity. Later we show that the shearlets provide very efficient representations for a large class of SIO. Shearlets are particularly useful in representing anisotropic functions due to the properties of an affine-like system of well-localized waveforms at various scales, locations, and orientations. This is a joint work with Dr. Niraj K. Shukla.
20 giugno 2019 - Aula 716 - Seminario di Working seminar Degenerations (Professoressa Chiara Camere)
17 giugno 2019 - Aula 713 - Seminario di Modal logic (Professor Riccardo Camerlo)
17 giugno 2019 - Aula 714 - Seminario di Analysis and Learning (Alberti)

ore 15:00-16:00 - Matteo Rizzi

"The relation between the Cahn-Hilliard equation and CMC surfaces"

Abstract: n the talk I will show the links between the Cahn-Hilliard equation
sabato 15 giugno 2019 - - Seminario
14 giugno 2019 - Aula 705 - Seminario di Prof. Riddhi Shah - New Delhi (Prof. Filippo De Mari Casareto dal Verme)

ore 15:00-16:30 - Prof. Riddhi Shah - New Delhi

"Distal Actions on Locally Compact Groups "

Abstract: Distal maps were introduced by David Hilbert on compact spaces to study non-ergodic maps. A homeomorphism T on a topological space X is said to be distal if the closure of every double T-orbit of (x, y) does not intersect the diagonal in X x X unless x=y. Similarly, a semigroup S of homeomorphisms of X is said to act distally on X if the closure of every S-orbit of (x,y) does not intersect the diagonal unless x=y. We discuss some properties of distal actions of automorphisms on locally compact groups and on homogeneous spaces given by quotients modulo closed invariant subgroups which are either compact or normal. We relate distality to the behaviour of orbits. We also characterise the behaviour of convolution powers of probability measures on the group in terms of the distality of inner automorphisms.
12 giugno 2019 - Aula 713 - Seminario di Algebra e Geometria (M. Penegini)

ore 14:00 - Gregory Pearlstein (Texas A&M University)

11 giugno 2019 - Aula 714 - Seminario di Algebra e Geometria (M. Varbaro)

ore 14:00 - Dilip Patil (Indian Institute of Science, Bangalore)

"Criterion for Rational points"

Abstract: The core of this talk is the equality of the number of $K$-rational points with the signature of the trace form of a finite $K$-algebra over a real closed field $K$. The main tools are symmetric bilinear forms, hermitian forms, trace forms, generalized trace forms and their types and signatures. Further, we prove a criterion for the existence of $K$-rational points by using generalized trace forms. As an application we prove the Pederson-Roy-Szpirglas theorem about counting common real zeros of real polynomial equations. We also deduce this theorem as a special case of a similar classical theorem for real closed fields.
11 giugno 2019 - Aula 713 - Seminario di Intertwining theorem for symmetric spaces (Dottor Matteo Monti)
11 giugno 2019 - Aula 716 - Seminario di Teoria degli insiemi (Professor Riccardo Camerlo)
6 giugno 2019 - Aula 714 - Seminario di Algebra e Geometria (Varbaro)

ore 15:00 - Alexandru Constantinescu (FU Berlin)

"Deformations of toric singularities"

Abstract: The possibilities of splitting a lattice polytope with primitive edges into a Minkowski sum of lattice polytopes reflect the deformation theory of the induced toric Gorenstein singularity. This was proved by Altmann in 1996. Our goal is to reveal a similar correspondence for arbitrary toric singularities. To this aim we define find an initial object among extensions of semigroups and define a lattice structure inside the cone of Minkowki summands.
6 giugno 2019 - Aula 714 - Seminario di Maximum of zeta on a short interval (Dottor Alessandro Fazzari)
5 giugno 2019 - Aula 705 - Seminario di Seminario Analisi Armonica (Dottoressa Francesca Bartolucci)
3 giugno 2019 - Aula 713 - Seminario di Modal logic (Riccardo Camerlo)
3 giugno 2019 - Aula 713 - Seminario (M. Benini)

ore 14:00-16:00 - M. Benini

31 maggio 2019 - Aula 704 - Seminario di Progetto Divulgazione (Rosolini)
31 maggio 2019 - Aula 715 - Seminario di Working seminar Degenerations (Camere)
29 maggio 2019 - Aula 715 - Seminario di Teoria degli Insiemi (Camerlo)
29 maggio 2019 - Aula 705 - Seminario di Category theory (Camerlo)

ore 14:00-16:00 - Cosimo Perini Brogi (University of Genoa)

27 maggio 2019 - Aula 705 - Seminario di Statistica (Riccomagno)

ore 14:00 - Prof. G. Pistone

"KANTOROVICH DISTANCE ON A WEIGHTED GRAPH"

Abstract: The computation of the Kantorovich distance (1-Wasserstein distance) on a finite state space may be a computationally hard problem in the case of a general distance. In this paper, we derive a simple closed form in the case of the geodesic distance on a weighted tree. Moreover, when the ground distance is defined by a graph, we show that the Kantorovich distance is the minimum of the distances on the spanning trees. See arXiv:1905.07547.

This is joint work with Luigi Montrucchio (Collegio Carlo Alberto). The presentation will be mainly a tutorial about Optimal Transport on a finite metric space.
23 maggio 2019 - Aula 713 - Seminario di Algebra e Geometria (M. Varbaro)

ore 13:00-14:00 - Prof. Ilya Smirnov (Stockholm University)

"Hilbert-Kunz multiplicity of the powers of an ideal."

Abstract: Hilbert-Kunz theory is a multiplicity theory native to positive characteristic. I will give an introduction to the subject and will present my recent result on its asymptotic behaviour when applied to the powers of an ideal.
22 maggio 2019 - Aula 713 - Seminario di Algebra e Geometria (M. Varbaro)

ore 15:00-16:00 - Prof. Bruno Benedetti (University of Miami)

"Graphs of polytopes"

Abstract:
21 maggio 2019 - Aula 715 - Seminario di PhD Seminar (N. Ginatta)

ore 15:00-16:00 - Tommaso Sorgente

21 maggio 2019 - Aula 704 - Seminario (Pinamonti)

ore 14:00-15:30 -

"Casimir energy and relative zeta function for a semitransparent plane"

Abstract:
17 maggio 2019 - Aula 713 - Seminario (M. Monti)

"Intertwining theorem for symmetric spaces"

16 maggio 2019 - Aula 716 - Seminario (C. Camere)

"Working seminar Degenerations"

14 maggio 2019 - Aula 704 - Seminario di Teoria e Applicazioni delle Categorie (Rosolini)
13 maggio 2019 - Aula 706 - Seminario di Teoria dei Numeri (Perelli)
9 maggio 2019 - Aula 716 - Seminario di Degenerations of algebraic varieties (Camere)
9 maggio 2019 - Aula 704 - Seminario (Pinamonti)

ore 16:00 - Prof. Felix Finster (University of Regensburg)

"Causal fermion systems and quantum field theory"

Abstract: The theory of causal fermion systems is an approach to describe fundamental physics. It gives quantum mechanics, general relativity and quantum field theory as limiting cases and is therefore a candidate for a unified physical theory. From the mathematical perspective, causal fermion systems provide a general framework for describing and analyzing non-smooth geometries. The dynamics is described by the so-called causal action principle. The aim of the talk is to give a simple introduction, with an emphasis on conservation laws (surface layer integrals) and the connection to quantum field theory.
8 maggio 2019 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - M. Penegini

""

Abstract:
7 maggio 2019 - Aula 714 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-16:00 - Lisa Nicklasson

""

Abstract:
6 maggio 2019 - Aula 714 - Seminario di Algebra e Geometria (Conca)

ore 13:00-14:00 - Duarte

3 maggio 2019 - Aula 715 - Seminario di Analisi armonica (M. Monti)
17 aprile 2019 - Aula 713 - Seminario di Algebra e Geometria (Penegini, Varbaro)

ore 14:00-16:00 - Daniele Zuddas, University Bayreuth

""

Abstract:
17 aprile 2019 - Aula 705 - Seminario di MIDA (Sorrentino)

ore 16:30-17:30 - Giuseppe Zampogna

"Reduced order solutions of the Navier-Stokes equations: an application to multi-scale fluid-structure interactions"

Abstract:
16 aprile 2019 - Aula 716 - Seminario di Analisi armonica (Bartolucci)
16 aprile 2019 - Aula 705 - Seminario di Analysis and Applications (Alberti)

ore 14:30-16:00 - Matteo Santacesaria

"Electrical impedance tomography and Calderon's inverse problem: a review"

Abstract: Calderon's inverse conductivity problem consists in the determination of an electrical conductivity distribution inside a body from current and voltage measurements on its boundary. Applications include medical imaging, nondestructive testing and geophysical prospecting. Since its formulation in 1980 it has stimulated a huge amount of research both in pure and applied mathematics. On the theoretical side, the main issue has been to prove uniqueness results, meaning the injectivity of the measurement or forward map, under appropriate assumptions on the regularity of the unknown conductivity, the amount of measurements and the geometry of the domain. Concerning applications, electrical impedance tomography (EIT) has been developed as the main imaging modality modeled by Calderon's problem. EIT faces great numerical hurdles, since errors in the data propagate exponentially to the reconstruction; in order to mitigate the instability (ill-posedness), strategies ranging from regularization methods, compressed sensing or machine learning have been employed. In this talk I will review the main results obtained for this problem and point out some theoretical and numerical challenges that are still open.
12 aprile 2019 - Aula 716 - Seminario di Fisica e matematica (Braga)
11 aprile 2019 - Aula 716 - Seminario di prof. Rosolini (Rosolini)
11 aprile 2019 - Aula 713 - Seminario di (Vigni)
10 aprile 2019 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-16:00 - Grzegorz Kapustka, Jagiellonian University Krakow

"Hilbert functions of local complete intersections"

Abstract: The sequences of positive integers that can occur as the Hilbert functions of graded complete intersections are well-known classically. However, the corresponding problem in the local case is completey open, once the embedding dimension is three or more. In this talk we will discuss the Hilbert functions of Artinian complete intersections in codimension three. This is my ongoing project with J. Jelisiejew M. E. Rossi.
9 aprile 2019 - Aula 705 - Seminario di Statistical Learning and optimization (Pagliana)

ore 15:00-16:30 - Christophe Giraud

9 aprile 2019 - Aula 714 - Seminario di The Dirichlet Polynomials (Fazzari)
3 aprile 2019 - Aula 705 - Seminario di Algebra e Geometria (Varbaro)
2 aprile 2019 - Aula 705 - Seminario di Analysis and Applications (Alberti)

ore 15:00-16:00 - Giulio Ciraolo

"On the shape of hypersurfaces with almost constant mean curvature"

Abstract:
26 marzo 2019 - aula 704 - Seminario di Analysis and Applications (Alberti)

ore 14:30-16:00 - Luca Rondi

"Multiscale decompositions in imaging and inverse problems
"

Abstract: We extend the hierarchical decomposition of an image as a sum of constituents of different scales, introduced by Tadmor, Nezzar and Vese in 2004, to a general setting. We develop a theory for multiscale decompositions which, besides extending the one of Tadmor, Nezzar and Vese to arbitrary L^2 functions, is applicable to a wide range of other imaging problems, such as image registration, or strictly related ones, such as nonlinear inverse problems. This is a joint work with Klas Modin and Adrian Nachman
20 marzo 2019 - Aula 508 - Seminario di MIDA seminar (Sorrentino)

ore 16:30-17:30 - Simone Marzani e Claudio Muselli, DIFI

"Ideas and tool in jet physics"

Abstract: We discuss the use of computer algorithms in high-energy particle physics. In particular, we focus on the physics of hadronic jets, i.e. collimated sprays of particles that appear ubiquitously in the analyses performed by the experiments at the CERN Large Hadron Collider. We discuss the algorithms that are employed to definite jets and modern machine learning techniques that are used to characterise their properties
20 marzo 2019 - Aula 508 - Seminario di Rubik's Cube (Varbaro)

ore 14:00-16:00 - Martin Kreuzer

"The Mathematics of the Rubik's Cube"

Abstract: In this talk we explore the connections between
twisty puzzles, in particular the Rubik's cube, and higher
algebra. It is suitable for a general mathematical audience.
Occasionaly, it will be interspersed with some mathematical
excursions into the underlying algebraic and algorithmic
theories.

More specifically, after giving a brief history of the invention
of Rubik's cube and how it became the best-selling toy
of all times, we introduce a mathematical model,
namely the Rubik's cube group.

Then we show how one can solve the cube using one
single four move algorithm (called a commutator).
We explain what God's number is, how God's algorithm
is related to the Buchberger procedure,
and how the theory of twisty puzzles leads to
new interesting problems in algebra.
20 marzo 2019 - Aula 713 - Seminario di fisica matematica (Pinamonti)

ore 16:00-17:30 - Daniel Siemssen

"Semiclassical Einstein equation"

Abstract: Einstein's equation describes the gravitational field in general relativity. Replacing in Einstein's equation the energy-momentum tensor of a classical field by the expectation value of the energy-momentum tensor of a quantum field, one arrives at the semiclassical Einstein equation. In this talk I will give an overview of the semiclassical Einstein equation and its formulation. I will also discuss approaches to solving this equation in cosmological spacetimes.
20 marzo 2019 - Aula 704 - Seminario di Optimal Transport And Gradient Flows (Villa)

ore 15:00-17:00 -

"Optimal transport and gradient flows
"

Abstract:
6 marzo 2019 - Aula 705 - Seminario di 2 cfu (ex crediti F) (Burlando)
28 febbraio 2019 - aula 704 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-16:00 - Alexandru Dimca, IUniversity of Nice-Sophia Antipolis

"On the Jacobian syzygies of projective plane curves"

Abstract: We discuss upper bounds on the number and degrees of generators
for the module of Jacobian syzygies of a plane curve.
Then we relate these invariants to some geometric properties of the curve.
27 febbraio 2019 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-16:00 - Mina Bigdeli, IPM, Tehran

"Chordal Complexes vs. Collapsible ones, and Componentwise linear ideals"

Abstract: In this talk, using the concept of d-collapsibility from combinatorial topology, we define chordal simplicial complexes and show that their Stanley-Reisner ideals are componentwise linear. We show d-collapsible and d-representable complexes produce componentwise linear ideals for appropriate d. Along the way, we prove that there are specific monomials we can add to the generating set of a monomial ideal without affecting the Betti numbers in certain degrees. Finally, giving some classes of componentwise linear ideals arising from chordal complexes, we conclude that the Betti table of every componentwise linear ideal is identical to that of the Stanley-Reisner ideal of a chordal complex.
18 febbraio 2019 - Aula 713 - Seminario di (Sasso, Balletti)

ore 14:30-15:30 -

"Structure of a covariant QMS with respect to an irreducible representation"

Abstract: We study the structure of a covariant Quantum Markov Semigroup (QMS) with respect to a generic irreducbile representation of a topological group. More precisely we characterize the generator of such QMS and its GKLS representation and also its decoherence free algebra.
In both cases we obtain a remarkable simplification of their structure compared to the general context due to the covariance.
Finally we show a connection between the number of connected components of the group and the number of factors in the decomposition of the decoherence free algebra.
7 febbraio 2019 - Aula 715 - Seminario di PhD (Ginatta)
5 febbraio 2019 - Aula 705 - Seminario (Villa)

ore 14:00-16:00 - Riccardo Zechina

"On The Existence And On The Role Of Wide Flat Minima In Deep Learning "

Abstract:
29 gennaio 2019 - Aula 713 - Seminario di algebra e geometria (Varbaro)

ore 14:00 - Mitra Koley (TIFR)

23 gennaio 2019 - Aula 713 - Seminario di Algebra&Geometry (Penegini, Varbaro)

ore 15:00-18:00 - Mitra Koley, Tata Institute of Fundamental Research

"F-rationality of Rees algebras"

Abstract: We will define the notion of F-rational rings (introduced by
Fedder and Watanabe). Then we will discuss F-rationality of Rees algebras.
21 gennaio 2019 - Aula 713 - Seminario di Algebra&Geometry (Varbaro)

ore 14:00-16:00 - Eduardo Saenz de Cabezon, universidad de la Rioja

"Depolarization of monomial ideals"

Abstract:
10 gennaio 2019 - Aula 713 - Seminario (Vigni)

ore 15:00-16:30 - Francesca Gatti, Universitat PolitÚcnica de Catalunya

"Non-crystalline generalized Kato classes and the values of the triple-product p-adic L-function at classical points"

Abstract: Let f ; g; h be three Hida families. The triple product p-adic L-function Lg
p(f ; g; h) interpolates
the central L-values L(fk
g`
hm; (k+`+m􀀀2)=2) for classical weights (k; `;m) such that `  k+m.
The point (2; 1; 1) lies outside the region of classical interpolation and L(f2
g1
h1; s) = L(E
; s),
where E is an elliptic curve over Q and  an Artin representation. Assume that it does not vanish
at s = 1. In this setting, we describe the value Lg
p(f ; g; h)(2; 1; 1) in terms of a non-cristalline
cohomology class which lies in the p-relaxed Selmer group attached to (E; ). It is a joint work
with X. Guitart, M. Masdeu, V. Rotger.
8 gennaio 2019 - Aula 713 - Seminario di algebra e geometria (Varbaro)

ore 14:00-16:00 - Federico Scavia, University of British Columbia

"Classi motiviche di gruppi lineari"

Abstract:
21 dicembre 2018 - Aula 713 - Seminario di MIDA seminar (Sorrentino)

ore 10:00-11:00 - Sara Sommariva, Aalto University, Helsinki

"An unsupervised clustering approach with spatial constraints for cortical parcellations based on the MEG forward model"

Abstract: Magnetoecephalography (MEG) is a modern neuroimaging technique capable of detecting the weak magnet fields produced by the brain. The analysis of MEG data typically consists in two steps. First a linear, ill-posed inverse problem is solved to reconstruct the neural activity. Then the statistical relationship between different brain areas is quantified by using metrics of functional connectivity. To this end realistic head models are employed where source spaces are defined to comprise thousands of possible source locations. Neural activity is estimated on the whole source space and connectivity metrics are computed between collapsed time courses of the source points within predefined regions of interest (ROIs). The fundamental limitations of such an approach are two: (i) the reconstructed sources are affected by spatial leakage artifacts due the ill-posedness of the MEG inverse problem; (ii) ROIs are typically defined based on anatomical properties of the brain and thus are not informed by the physics of the investigated inverse problem.
In this talk I will discuss the application of FLAME [1], an unsupervised fuzzy clustering approach, to subsample and cluster the source space according to the leadfield matrix defining the MEG forward model. More in details, first I will present the similarity measure we designed to group the source points, which consists in a convex combination of the adjusted cosine similarity between the columns of the leadfield and a spatial distance promoting the spatial cohesion of the clusters. Then I will discuss structural and functional properties of the obtained parcellations.
20 dicembre 2018 - Aula 713 - Seminario di Teoria e Applicazioni delle Categorie (Rosolini)

ore 17:30-19:00 - Enrico Ghiorzi, University of Cambridge

"Categorie interne arricchite"

Abstract:
19 dicembre 2018 - Aula 716 - Seminario di Fisica Matematica - Simone Murro (Pinamonti)

"On the Cauchy problem for the Dirac operator
"

Abstract:
11 dicembre 2018 - Aula 705 - Seminario di Machine Learning (De Vito)

ore 14:30-16:00 - Andreas Maurer

"Weak interactions"

Abstract: The talk is about a class of statistics with the following second-order stability property: their variation in any variable does not change much when another variable is modified. Besides linear statistics this class contains U- and V-statistics, Lipschitz L-statistics and some extremal estimators. Respective examples relevant to machine learning would be the area under the ROC curve, smoothened quantiles and various error functionals of l_2-regularized algorithms.
These statistics behave in many ways like linear statistics: they obey a version of Bernstein's inequality, their variances can be tightly estimated from iid samples, and there is a Berry-Esseen type bound on normal approximation. There even is a uniform concentration result, which generalizes the popular generalization bounds obtained with Gaussian and Rademacher complexities.
6 dicembre 2018 - Aula 714 - Seminario di MIDA seminar -- Mariarosa Mazza (Sorrentino)

ore 15:00-16:00 - Maria Rosa Mazza, Universita dell'Insubria, Como

"Generalized locally Toeplitz sequences and some applications to MHD subproblems"

Abstract:
5 dicembre 2018 - Aula 705 - Seminario di Algebra&Geometry (Varbaro)

ore 15:00-16:00 - Michela Ceria, University of Trento

"DIY for Groebner bases: multivariate Ore extensions"

Abstract:
3 dicembre 2018 - Aula 704 - Seminario di MIDA (Sorrentino)

ore 15:00-16:00 - Prof. Luca Formaggia, MOX, Dipartimento di Matematica, Politecnico di Milano

"Some mathematical and numerical issues in the modelling of underground flow and fault reactivation"

Abstract: The exploitation of subsoil (oil/gas extraction, CO2 sequestration, geothermal energy) often involves the injection of fluids with a consequent alteration of the pore pressure. This alteration of the state of stress may induce the activation of nearby faults with the risk of a seismic event. Modelling the stress state and the consequences on fault stability is a challenging task that involves coupling poromechanics with frictional contact models in a heterogeneous and fractured media.
In this presentation, we will give an overview of recent activity at the MOX Laboratory on modelling fault reactivation due to underground exploitation. We will first present some numerical models for flow in fractured media and some synthetic and realistic simulations obtained by coupling standard underground flow and geomechanical solvers to account the effect of pore pressure alteration on the stability of faults. We will also give a brief report on recent preliminary activity on models that account for full poroelasticity/frictional contact problem and uncertainty quantification.
30 novembre 2018 - Aula 716 - Seminario di MIDA seminar -- Matteo Alparone (Sorrentino)

ore 14:30-15:30 - Matteo Alparone

"Inverse problems arising from microwave remote sensing: spatial resolution of the radiometer products"

Abstract: A broad class of problems arising in physics or engineering consists of finding a function f such that a known operator L transforms f into a given function b. Basically, L is the so-called forward operator, which represents the known mathematical model, b is the known data, and f is the unknown to retrieve. These problems usually belong to the class of inverse problems, such as identification, synthesis, reconstruction, inverse scattering, image restoration, etc...

The basic inverse problem arising in microwave applications can be formulated according to a linear integral equation, i.e.; a Fredholm equation of the first kind, that describes the relationship between the measurements and the unknown function through a smooth kernel. When a microwave device is considered, the kernel is the low-pass system aperture function and, hence, the resulting inverse problem is ill-posed. Hence, regularization techniques must be invoked to obtain a reliable solution. In addition, to solve the linear system resulting from the discretization of integral equation, we have to consider the structure of the system, which can be full determined, overdetermined, and underdetermined.

In this seminar, the underdetermined case will be discussed since it typically applies when dealing with spatial resolution enhancement of microwave remotely sensed measurements, where coarse but partially correlated measurements are exploited to reconstruct the signal on a finer resolution grid. Methods will be described to enhance the spatial resolution of single-pass radiometer measurements by solving the related ill-posed inverse problem in both Hilbert and Banach spaces.
30 novembre 2018 - Aula 705 - Seminario di Algebra&Geometry (Varbaro)
28 novembre 2018 - Aula 705 - Seminario di Algebra&Geometry (Varbaro)

ore 12:00-18:00 - Shreedevi Masuti, Chennai Mathematical Institute

"The structure of the inverse system of level K-algebras"

Abstract:
14 novembre 2018 - Aula 704 - Seminario di Algebra e Geometria (ex aula 713) (Penegini, Varbaro)

ore 13:30-15:45 - Alice Garbagnati, University of Milan

"K3 surfaces covered by K3 surfaces and symplectic automorphisms"

Abstract: The finite symplectic automorphisms on K3 surfaces create a relation between different families of K3 surfaces. Indeed the minimal resolution of the quotient of a K3 surface by an automorphism is (another) K3 surface if and only if the automorphism is symplectic. The families of K3 surfaces admitting a symplectic automorphism are known and well described in terms of lattice polarized K3 surfaces. More recently, also the families of K3 surfaces obtained as quotient of a K3 surface by a symplectic automorphism (so which are covered by a K3 surface) were described in terms of lattice polarized K3 surfaces. After reviewing these results we discuss the natural problem: what is the intersection between these families? I.e are there families of K3 surfaces which are both covers of K3 surfaces and covered by K3 surfaces? The main results are obtained for the symplectic involutions, but some of them can be extended to automorphisms of higher order. This last part of the talk is based on a joint work with C. Camere.
14 novembre 2018 - Aula 716 - Seminario di TdN (Perelli)
9 novembre 2018 - Aula 713 - Seminario di Logic and categories (Camerlo)

Pagina web

ore 9:00-11:00 - prof. Giuseppe Rosolini, University of Genoa

"Completamenti di categorie e applicazioni"

Abstract: La teoria delle categorie permette di studiare le teorie logiche nella forma di strutture algebriche. Per questo e' possibile eseguire costruzioni libere su una teoria. Vedremo in particolare il completamento per quozienti di una dottrina elementare, introdotto insieme con Maria Emilia Maietti per studiare modelli della teoria Minimalist Foundation di Maietti e Sambin.
In seguito, applicheremo quella costruzione a alcune teorie logiche particolari per suggerire possibili collegamenti con teoria descrittiva degli insiemi.
8 novembre 2018 - Aula 706 - Seminario di JMP (Riccomagno)
7 novembre 2018 - Aula 716 - Seminario di Teoria dei numeri (Bettin)
30 ottobre 2018 - Aula 704 - Seminario di Algebra e Geometria (Varbaro)

ore 16:30 - Francesco Galuppi (MPI Leipzig)

"Signature varieties of rough paths"

Abstract: Given a path X, its signature is a sequence of tensors encoding geometric features of X. We study signature tensors from an algebraic geometric viewpoint. The signatures of a given class of paths parametrize a variety inside the space of tensors, and these signature varieties provide both new tools to investigate paths and new challenging questions about their behavior. We focus on signatures of rough paths. Their signature variety shows surprising analogies with the Veronese variety, and our aim is to study its geometry.
24 ottobre 2018 - Aula 716 - Seminario di Ph.D. Seminars (Faldino)
19 ottobre 2018 - Aula 716 - Seminario di Logic and categories (Camerlo)

ore 9:30-10:30 - prof. Giuseppe Rosolini (University of Genoa)

"Completamenti di categorie e applicazioni"

Abstract: La teoria delle categorie permette di studiare le teorie logiche nella forma di strutture algebriche. Per questo e' possibile eseguire costruzioni libere su una teoria. Vedremo in particolare il completamento per quozienti di una dottrina elementare, introdotto insieme con Maria Emilia Maietti per studiare modelli della teoria Minimalist Foundation di Maietti e Sambin.
In seguito, applicheremo quella costruzione a alcune teorie logiche particolari per suggerire possibili collegamenti con teoria descrittiva degli insiemi.
16 ottobre 2018 - Aula 713 - Seminario di Fisica Matematica (Pinamonti)

ore 14:30-16:00 - Kasia Rejzner, University of York

"Construction of models in perturbative algebraic quantum field theory"

Abstract: In this talk I will give a short introduction into the framework of perturbative algebraic quantum field theory, which is a mathematically rigorous formulation of perturbative QFT. I will also explain how to construct interacting models using the concept of relative S-matrices and present the example in which this construction leads to non-perturbative results (sine-Gordon model)
20 settembre 2018 - Aula 716 - Seminario di Homotopy Type Theory Electronic Seminar (Rosolini)

ore 17:00-19:00 - Andrew Pitts, University of Cambridge

"Axiomatizing Cubical Sets Models of Univalent Foundations
"

Abstract:
17 settembre 2018 - Aula 713 - Seminario di Fisica Matematica (Pinamonti)

ore 14:30-16:00 -

"Wavepackets on de Sitter spacetime"

Abstract: We construct wavepackets on de Sitter spacetime, with masses consistently defined from the eigenvalues of an irreducible representation of a Casimir element in the universal enveloping algebra of the Lorentz algebra and analyze their asymptotic behaviour. Furthermore, we show that, in the limit as the de Sitter radius tends to infinity, the wavepackets tend to the wavepackets of Minkowski spacetime and the plane waves arising after contraction have support sharply located on the mass shell.
11 settembre 2018 - Aula 705 - Seminario di PhD Colloquim (Pinamonti)

ore 11:00-13:00 - Prof. Yiannis Petridis, UCL

"Quadratic forms, closed geodesics, and periods"

Abstract: Quadratic forms have been studied from many points of view. We will see how equivalence of quadratic forms and solving certain Pell's equations connects to the geometry of the hyperbolic plane and the geodesics of the simplest hyperbolic surface, which has fundamental group SL(2, Z).
The study of the lengths of such closed geodesics presents analogies with the Prime Number Theorem. We will survey some recents developments in this direction and its relation to modular symbols and additive twists of L-functions.
4 settembre 2018 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 13:00-17:00 - Prof. Meng Chen, Fudan University Shanghai

"The regularity of the partial elimination ideals and related problems"

Abstract:
26 luglio 2018 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Sijong Kwak (Korea Advanced Institute of Science and Technology)

"The regularity of the partial elimination ideals and related problems"

Abstract:

ore 15:30 - Jongil Park (Seoul National University)

"Symplectic fillings versus Milnor fibers of a quotient surface
singularity"

Abstract: One of active research areas in symplectic 4-manifolds is to classify symplectic llings of certain 3-manifolds equipped with a contact structure. Among them, people have long studied symplectic fillings of the link of a quotient surface singularity. Note that the link of a quotient surface singularity carries a canonical contact
structure which is also known as the Milnor fillable contact structure. One the other hand, algebraic geometers also have studied Milnor fibers as a general fiber of smoothings for a quotient surface singularity.
In this talk, I'd like to review known results on symplectic fillings and Milnor fibers of quotient surface singularities and to explain a relation between minimal symplectic fillings and Milnor fibers of quotient surface singularities. This is a joint work with Heesang Park, Dongsoo Shin, and Giancarlo Urzua.
11 luglio 2018 - Aula 715 - Seminario di Teoria dei numeri (Cherubini)
11 luglio 2018 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 14:00 - Wenfei Liu (University of Xiamen)

"On accumulation points of volumes of log surfaces"

Abstract:
9 luglio 2018 - Aula 714 - Seminario di Algebra e Geometria (Varbaro)

ore 14:15 - Bruno Benedetti (University of Miami)

"SOME CONTRACTIBLE 2-COMPLEXES CANNOT BE DRAWN IN R4"

Abstract:
22 giugno 2018 - Aula 716 - Seminario (Pesce)
11 giugno 2018 - Aula 715 - Seminario di PhD Seminars (Bartolucci)
8 giugno 2018 - Aula 713 - Seminario di statistica (Rogantin)
4 giugno 2018 - Aula 704 - Seminario di Matematica Applicata (Estatico)

ore 11:00-12:00 - Raymond H. Chan, Department of Mathematics, The Chinese University of Hong Kong; SIAM Council member

"Flexible methodology for image segmentation"

Abstract: In this talk, we introduce a SaT (Smoothing and Thresholding) method for multiphase segmentation of images corrupted with different degradations: noise, information loss and blur. At the first stage, a convex variant of the Mumford-Shah model is applied to obtain a smooth image. We show that the model has unique solution under different degradations. In the second stage, we apply clustering and thresholding techniques to find the segmentation. The number of phases is only required in the last stage, so users can modify it without the need of repeating the first stage again. The methodology can be applied to various kind of segmentation problems, including color image segmentation, hyper-spectral image classification, and point cloud segmentation. Experiments demonstrate that our SaT method gives excellent results in terms of segmentation quality and CPU time in comparison with other state-of-the-art methods
29 maggio 2018 - Aula 705 - Seminario di Analisi Armonica (Astengo)

ore 15:00-18:00 -

"Exhaustion functions, Laplacian cut-offs and applications"

ore 15:35-16:05 - Mattia Calzi, SNS Pisa

"Moltiplicatori spettrali su gruppi omogenei"

ore 16:10-16:40 -

"Moltiplicatori $L^p$ sugli alberi"

ore 16:45-17:15 -

"Wavelets, shearlets e la trasformata di Radon"

29 maggio 2018 - Aula 704 - Seminario di Analisi Armonica (Astengo)

ore 10:30-13:00 - Michael Cowling, UNSW Sydney

"Generalizzazioni di un teorema di Darboux
"

ore 11:05-11:35 - Maria Vallarino, Politecnico di Torino

"Un teorema di moltiplicatori per sub-Laplaciani con drift su gruppi di Lie"

ore 11:35-12:05 - Tommaso Bruno, Politecnico di Torino

"Spazi di Sobolev su gruppi di Lie"

ore 12:10-12:40 -

"Stime asintotiche per la varianza del numero di punti interi in un anello
"

28 maggio 2018 - Aula 713 - Seminario di TdN (Perelli)
23 maggio 2018 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Prof. Jugal Verma (IIT Bombay)

""

Abstract:
22 maggio 2018 - Aula 715 - Seminario di Continuazione Seminario del corso del Prof. Verma (Rossi)
21 maggio 2018 - Aula 706 - Seminario di Corso Prof. Verma (Rossi)
16 maggio 2018 - Aula 713 - Seminario di Algebra&Geometry (Varbaro)

ore 14:30 - Dipankar Ghosh (Chennai Mathematical Institute)

"Asymptotic linear bounds of Castelnuovo-Mumford regularity"

Abstract: I will speak on asymptotic linear bounds of Castelnuovo-Mumford regularity involving powers of homogeneous ideals in a polynomial ring over a field. The regularity of powers of a single ideal is well understood. A natural question arises what happens when we consider more than one ideals? We prove that in this case also there is a linear upper bound. Our result is over a standard graded algebra over an Artinian local ring. In another work (joint with Tony J. Puthenpurakal), we show a linear upper bound of regularity of certain Ext modules involving powers of homogeneous ideals over complete intersection rings
16 maggio 2018 - Aula 705 - Seminario di Fisica Matematica (Martinetti)

ore 16:30-18:30 -

"Non commutative curved spacetimes from the DFR point of view: some results and open problems"

Abstract: After a review of the basic ideas and motivations of the Doplicher-Fredenhagen-Roberts approach to (semiclassical) Quantum Gravity
through the basic example of the minkowskian case, we will discuss some known results and ongoing work for more general curved spacetimes
9 maggio 2018 - Aula 713 - Seminario di Teoria dei Numeri (Vigni)

ore 17:00 -

""

Abstract:
8 maggio 2018 - Aula 706 - Seminario di PhD Colloquium (Pinamonti)

ore 14:00-16:00 - Professor Tai Huy Ha, Tulane University

"Powers of sums of ideals"

Abstract: Let $A = k[x_1, dots, x_r]$ and $B = k[y_1, dots, y_s]$ be polynomial rings over a field $k$, and let $I subseteq A$ and $J subseteq B$ be nonzero proper homogeneous ideals. We shall discuss algebraic invariants and properties of both symbolic and ordinary powers of the ideal $I+J subseteq R = A otimes_k B$. This investigation leads to the proof of a conjecture of Herzog and Hibi on possible depth functions of ideals
26 aprile 2018 - Aula 714 - Seminario di PhD Seminars (Bartolucci)
23 aprile 2018 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
19 aprile 2018 - Aula 715 - Seminario di Seminario Samuele Antonini (Morselli)
18 aprile 2018 - Aula 704 - Seminario di Teorie delle Categorie (Rosolini)
18 aprile 2018 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:15 - Alessio Caminata (University of Barcelona)

"Equations for point configurations to lie on a rational normal curve"

Abstract: We consider the compactification $V_{d,n}$ of the space of configurations of n distinct points supported on a rational normal curve of degree d in a d-dimensional projective space. We discuss the problem of finding equations that define $V_{d,n}$ (set-theoretically and scheme-theoretically), and its applications. This is a joint work with Noah Giansiracusa, Han-Bom Moon, and Luca Schaffler.
13 aprile 2018 - Aula 705 - Seminario di MIDA - Prof. Bruno Burlando (Sorrentino)

ore 14:30-15:30 - Prof. Bruno Burlando, Dipartimento di Farmacia, Genova

"Loopomics: a new paradigm for the functioning of living beings"

Abstract: A new paradigm is proposed for the functioning of living beings. Organisms are thought of as a complex of functional agents (FA), where each FA is controlled upstream by at least one FA and controls downstream at least one FA, entailing that every FA is embedded in at least one functional loop. The term loopomics is proposed for this kind of analysis, aimed at describing the organism functioning in terms of FA loop networks. Loopomics is prone to formalization, and therefore, future development is aimed at developing mathematical models to be verified on molecular biology and physiology data. Once validated, such a new approach could allow a reinterpretation of physiological and pathological processes, thus opening a wide range of possible applications.
10 aprile 2018 - Aula 715 - Seminario di Teoria dei Numeri (Perelli)
5 aprile 2018 - Aula 705 - Seminario di Seminario di Statistica (Riccomagno)

ore 14:00-16:00 - Beniamino Hadj-Amar, Department of Statistics, The University of Warwick (UK)

"Simultaneous Bayesian model search and change-points detection for non-stationary oscillatory processes.
"

Abstract: The analysis of time series that show oscillatory and - more or less - periodic behaviour is a common task in many sciences. In particular, the non-stationary analysis of cyclical data that show regime shifts in periodicity, amplitude and phase is challenging as the timing and number of such changes is usually unknown. We propose a methodology for detecting such regime shifts using several Bayesian transdimensional Markov chain Monte Carlo algorithms which allow for model searches between parameters subspaces of different dimensionality. Our algorithm incorporates multiple model searches, namely the number of regimes and the harmonic models that capture the relevant frequencies along with their amplitudes and phases within each regime. We illustrate the use of the methodology for data from experiments on rodents to detect instances of sleep apnoea.
This is joint work with Barbel Finkenstadt. Manuele Leonelli, School of Mathematics and Statistics, University of Glasgow

"Change point identification of extreme regimes"

Abstract: Precise knowledge of the tail behaviour of a distribution as well as predicting capabilities about the occurrence of extremes are fundamental in many areas of applications, and in particular for financial time series. Standard inferential routines for extremes require the imposition of arbitrary assumptions which may negatively affect the statistical estimates. The model class of extreme value mixture models, on the other hand, allows for the precise estimation of the tail of a distribution without requiring any arbitrary assumption. Here we extend this model class to handle situations where different extreme structures may be useful to perform inference over the extremes of a time series. This is achieved by proposing a novel changepoint approach for extremes, where the changepoints are estimated via Bayesian MCMC routines. Our approach is evaluated through a series of simulations, applied to real financial data sets and assessed against competing approaches. Evidence demonstrates that the inclusion of changepoints improves the goodness of the extreme estimation in financial applications.
27 marzo 2018 - Aula 704 - Seminario di MIDA (Sorrentino)

ore 15:00-16:00 - Maria Carla Piastra, Institute for Biomagnetism and Biosignal analysis, University of Munster

"Finite Element Methods to solve the EEG, MEG or combined EEG/MEG forward problem and their applications."

Abstract: Electroencephalography (EEG) and magnetoencephalography (MEG) are techniques used to investigate brain activity. EEG and MEG are devoted to detect the electric potential distribution and the magnetic field generated by the brain, respectively, with a unique time resolution. An important topic in many applications of EEG and MEG is the source reconstruction, i.e., the identification of the sources in the brain responsible for the signals recorded at the head surface (EEG) or in a small distance from the head surface (MEG). Moreover, it has been shown that combined EEG/MEG employs the complementary information of both modalities providing source reconstructions that outperform the ones provided by each single modality. In order to compute EEG/MEG source reconstructions, i.e., to solve a related ill-posed inverse problem of EEG/MEG, the forward problem has to be solved. Since the accuracy of EEG/MEG inverse problem solutions depends strongly on the forward solution, it is fundamental to increase the accuracy of the latter. Furthermore, in a multi-modal EEG/MEG reconstruction it is desirable to use the same forward model for both EEG and MEG data.
The focus of this talk is on Galerkin Finite Element Methods (FEMs) to solve the EEG, MEG, and combined EEG/MEG forward problem and their applications.
The presentation is divided into three main topics: (1) introduction to FEMs for solving the EEG, MEG or combined EEG/MEG forward problem; (2) the Discontinuous Galerking FEM for solving the MEG and the combined MEG/EEG forward problem; (3) sensitivity of Signal-to-Noise Ratio maps of cortical and subcortical sources in EEG and MEG to realistic head modeling.
20 marzo 2018 - Aula 716 - Seminario di PhD Seminars (Bartolucci)
20 marzo 2018 - Aula 704 - Seminario di MIDA (Sorrentino)

ore 11:00-13:00 - Prof de' Michieli Vitturi, Istituto Nazionale di Geofisica e Vulcanologia

"Numerical models of volcanic plumes: uncertainty quantification and sensitivity analysis"

Abstract: When studying volcanic processes and the associated hazard, our understanding of the physical system is often very limited. In particular, for volcanic plumes produced by explosive eruptions, the physical parameters controlling them (gas content, temperature, particle size distribution, etc.) are often not well constrained or are characterized by significant uncertainties, making difficult to predict with certainty the characteristic of the ash cloud released into the atmosphere by the volcanic column. An alternative is to quantify the probability of the results (for example the particle size distribution at the top of the column) by coupling deterministic numerical codes with stochastic approaches. In this presentation, after an introduction on volcanic plumes and their physical-mathematical modeling, I will present some techniques to systematically quantify the uncertainty and sensitivity of the model results to uncertain or variable input parameters, especially to those characterizing the ash size distribution at the base of the eruptive column. In particular, attention will be focused on techniques such as Monte Carlo methods, Latin Hypercube Sampling, and the polynomial chaos expansion.
19 marzo 2018 - Aula 706 - Seminario di machine learning (De Vito)

ore 15:30-16:30 - Gergely Neu, University Pompeu Fabra, Barcelona

"Iterate averaging as regularization for stochastic gradient descent
"

Abstract: We propose and analyze a variant of the classic Polyak-Ruppert
averaging scheme, broadly used in stochastic gradient methods. Rather
than a uniform average of the iterates, we consider a weighted
average, with weights decaying in a geometric fashion. In the context
of linear least squares regression, we show that this averaging scheme
has a the same regularizing effect, and indeed is asymptotically
equivalent, to ridge regression. In particular, we derive
finite-sample bounds for the proposed approach that match the best
known results for regularized stochastic gradient methods.
8 marzo 2018 - Aula 509 - Seminario (Rosolini)
27 febbraio 2018 - Aula 715 - Seminario di Teoria dei Numeri (Perelli)
26 febbraio 2018 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 15:00 -

""

Abstract:
21 febbraio 2018 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
21 febbraio 2018 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 -

"On stratifications of the moduli space of Jacobian elliptic K3"

Abstract: The moduli space was constructed by Miranda as a quotient of quasi-projective space of dimension 22 by a reductive group of dimension 4.
I want to survey stratifications coming from geometric properties related to the elliptic fibration on each surface on one hand and the stratification by the Neron-Severi group on the other hand.
The final focus will be on moduli subspaces which fit with the Neron-Severi stratification of Shimada and the stratification by monodromy groups of Bogomolov Pantev and Tschinkel, for which I will give a complete classification.
(joint work with K.Hulek).

ore 15:00 -

"A new question on planar polynomial interpolation and line arrangements"

Abstract: Polynomial interpolation problems have been largely studied in algebraic geometry and commutative algebra. The classical question is the following: how many independent conditions a general union of fat points in P^2 imposes on the complete linear system of plane curves of given degree? A conjectural answer to this question is given by the famous SHGH Conjecture (due to B. Segre, B. Harbourne, A. Gimigliano and A. Hirschowitz) which has been proven to be true in some cases but, in general, is still open. In a recent paper, D. Cook II, B. Harbourne, J. Migliore and U. Nagel, started to investigate a different question by looking at the conditions imposed by one general fat point on the incomplete linear system of curves of given degree passing through a given set of points X (not in general position). There are cases in which the expected number of conditions is not achieved and we have unexpected curves. In their work, they relate the existence of unexpected curves with properties of the line arrangement dual to the given set of points X. In particular, to the splitting type of the arrangement.

In this talk, after describing the problem and the relation between unexpected curves and line arrangements, I will present a joint project with M. Di Marca (U. of Genova, Italy) and G. Malara (Pedagogical U. of Cracow, Poland). We classify supersolvable line arrangements whose dual configuration of points admits unexpected curves and we provide new families of line arrangements having this unexpected property.
20 febbraio 2018 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
15 febbraio 2018 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
14 febbraio 2018 - Aula 706 - Seminario (Luca Oneto)

ore 9:30-13:30 - Maria Fasli, Director, Institute for Analytics and Data Science (IADS), University of Essex

"Exploring Complex & Big Data: Towards Smart Delegation"

Abstract: With the rapid growth of computational devices being used in almost all aspects of human activity, we have seen an explosion in the volumes of data, both structured and unstructured, being generated in a range of domains. This talk will be describing some of the issues and challenges arising in analysing and modeling big and complex data. The presentation will discuss work that has been using artificial intelligence techniques such as agent-based and multi-agent systems, to explore and understand complex and big data in different domains of application, ranging from understanding the dynamics of electronic markets to individual user behaviour in domains such as commerce and education. Ethical and legal considerations on the use of algorithms for various forms of decision making will also be discussed.
7 febbraio 2018 - Aula 716 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Alberto F. Boix (Ben-Gurion University)

"Free pairs of a simplicial complex, and an application"

1 febbraio 2018 - Aula 713 - Seminario di PhD Seminars (Faldino)
26 gennaio 2018 - Aula 715 - Seminario di (Sasso)

""

25 gennaio 2018 - Aula 706 - Seminario di PhD Colloquium (Pinamonti)

ore 14:30-16:00 - Prof. Nenad Teofanov (University of Novi Sad)

"Wave front sets and related topics "

Abstract:
24 gennaio 2018 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Rahim Zaare-Nahandi (University of Tehran)

"Cohen-Macaulay simplicial complexes in arbitrary codimension"

Abstract: A simplicial complex of dimension d-1 is said to be Cohen-Macaulay in codimension t, 0 <= t <= d-1, if it is pure and the link of any face with cardinality at least t is Cohen-Macaulay. This generalizes several concepts on simplicial complexes such as Cohen-Macaualy-ness, Buchsbaum property, S_r condition of Serre, and locally Cohen-Macaulay-ness.
Most results on the simplicial complexes with aforementioned properties naturally extend to the case of Cohen-Macaulay-ness in codimension t under weaker assumptions. In particular, the classical Eagon-Reiner theorem, the local behavior and the homological vanishing properties are suitably retained for Cohen-Macaulay-ness in codimension t. Furthermore, characterizations of certain families of Cohen-Macaulay simplicial complexes carry over characterizations of these families of simplicial complexes which are Cohen-Macaulay in codimension t. The connection between the $S_r$ condition and Chen-Macaulay-ness in codimension t reveals that this property is a topological invariant of the family of the Alexander dual
of flag complexes. This is not known for arbitrary complexes.
This talk is based on recent joint works with H. Haghighi, S. A. S. Fakhari, M. Varbaro and S. Yassemi
17 gennaio 2018 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 -

"Computer Aided Geometric Constructions from the Perspective of Algebraic Geometry"

Abstract: In many problems in Computer Aided Geometric Design (CAGD) the main mathematical objects are algebraic curves and algebraic surfaces, and hence interesting questions related to algebraic geometry arise. This fact generates a very useful synergy between the two fields, CAGD and the theory of curves and surfaces.In this talk we will illustrate how the interpretation of some of these problems, from the perspective of algebraic geometry, helps to derive interesting theoretical and algorithmic results. For this purpose, we will survey on results on offset varieties as well as on other CAGD constructions as conchoids, cissoids and bisectors. Special attention will be paid to the unirationality of the construction.Some of the results to be presented to this talk has been developed under the frame of the research project MTM2014-54141-P (Ministerio de Econom'ia y Competitividad).
12 gennaio 2018 - Aula 713 - Seminario (Rosolini)
9 gennaio 2018 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 -

"Orbital degeneracy loci"

Abstract: In a joint project with Vladimiro Benedetti, Sara Angela Filippini, and Laurent Manivel, we introduce a new class of varieties, called orbital degeneracy loci. The base idea is to use any orbit closure in a representation of an algebraic group to generalize classical degeneracy loci of morphisms between vector bundles or zero loci of sections. In this talk I will introduce some tools to understand and study this new class of objects; with such techniques, we can exploit our construction to produce several interesting examples of projective varieties, in particular varieties with trivial or negative canonical bundle.
20 dicembre 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - Alessandro De Stefani (University of Nebraska-Lincoln)

"Symbolic powers in mixed characteristic"

Abstract:

ore 15:00 - Michela Cerio (University of Trento)

"Combinatorics of involutive divisions"

Abstract:
19 dicembre 2017 - Aula 714 - Seminario di Didattica della Matematica (Morselli)

ore 9:30-11:00 - Bettina Pedemonte (San Jose State University)

""

19 dicembre 2017 - Aula 714 - Seminario di Teoria ed Applicazioni delle categorie (Rosolini)

ore 11:00-13:00 - Alessio Santamaria

ore 12:00-13:00 - Fabio Pasquali

13 dicembre 2017 - Aula 713 - Seminario (Bartocci)

ore 14:30 -

"Qualche nota sulle relazioni fra logica e geometria"

6 dicembre 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)
5 dicembre 2017 - Aula 713 - Seminario di MIDA (Sorrentino)

ore 12:00-13:00 - Prof. Maurizio Falcone, Dipartimento di Matematica, Universita di Roma La Sapienza

"Semi-Lagrangian schemes for nonlinear PDEs in image processing"

Abstract: The PDE approach to the solution of image processing problems has been rather successful in the last 30 years opening new directions in the field.
Typically the PDEs appearing in some classical problems like Shape from Shading, segmentation and filtering are nonlinear and often degenerate so that standard numerical methods for their approximation can not be applied.
We describe a class of numerical schemes for first and second order nonlinear PDEs based on semi-lagrangian (SL) techniques. Those methods have been originally applied for simple advection equations, more recently they have been extended to deal with a wide range of nonlinear possibly degenerate differential problems.
The main advantage is that SL schemes have strong stability properties and allow for large time steps still providing accurate solutions. We will give a short review of these properties as well as some applications to some classical image processing problems.
29 novembre 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)
23 novembre 2017 - Aula 713 - Seminario di Teoria ed Applicazioni delle categorie (Rosolini)

ore 14:30-16:30 - Luigi Santocanale (AMU, Marseille)

"Decidability of the equational theory of the natural join and the inner
union"

Abstract:
22 novembre 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 14:30 - Cinzia Casagrande (University of Turin)

"The blow-up of P^4 in 8 points and its Fano model, via moduli of vector bundles on a degree 1 del Pezzo surface"

Abstract: Mukai has realised the blow-up X of P^4 in 8 general points as a moduli space of vector bundles on a degree 1 del Pezzo surface S. With the same construction, we associate to S a (smooth) Fano 4-fold Y, which is isomorphic to X in codimension 1. We will explain the interplay between S, X, and Y, which allows to describe many geometrical properties of X and Y, in particular in relation to birational geometry. For instance, we will describe the relevant cones of divisors and the Mori chamber decomposition of these 4-folds. We will see that the Fano 4-fold Y has an interesting geometry; it has b_2(Y)=9, (K_Y)^4=13, and dim|-K_Y|=5. The linear system |-K_Y| has non-empty base locus, while |-2K_Y| is base-point-free. The second cohomology group H^2(Y,Z) has a lattice structure such that the ortogonal of the canonical class is an E_8-lattice; the associated Weyl group fixes the cones of effective, movable and nef divisors, and permutes the chambers of the Mori chamber decomposition.
This is a joint work with Giulio Codogni and Andrea Fanelli.
16 novembre 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 15:30 -

""

Abstract:
15 novembre 2017 - Aula 508 - Seminario di Algebra e Geometria (Penegini)

ore 14:30 -

"Superfici K3 e loro sezioni iperpiane"

Abstract:
14 novembre 2017 - Aula 713 - Seminario (Perelli)

ore 14:30-15:30 - prof. Kaczorowskif

10 novembre 2017 - Aula 713 - Seminario (Perelli)

ore 14:30-15:30 - prof. Kaczorowskif

8 novembre 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 14:30 - Carla Novelli (University of Padova)

""

Abstract:
7 novembre 2017 - Aula 713 - Seminario (Perelli)

ore 14:30-15:30 - prof. Kaczorowskif

2 novembre 2017 - Aula 704 - Seminario di Complexity in set theory (and beyond) (Rosolini)

ore 15:00 - Riccardo Camerlo, Politecnico di Torino

"Complexity in set theory (and beyond)"

Abstract: I will survey descriptive set theoretic ways to deal with the notion of complexity, starting with sets and then moving to classification problems, with the aim to demonstrate how this fits with current mathematical practice.
31 ottobre 2017 - Aula 713 - Seminario (Perelli)

ore 14:30-15:30 - prof. Kaczorowskif

26 ottobre 2017 - Aula 713 - Seminario di Fisica Matematica (Pinamonti)

ore 14:30-16:00 - Daniela Cadamuro

"Lower bounds for the energy density in quantum integrable models"

Abstract: The energy density is classically positive, a property that fails to be true in quantum theory. However, if it were indefinitely negative, it might produce macroscopic violations of the second law of Thermodynamics or allow the existence of exotic spacetimes configurations (such as wormholes, time machines and warp drives). Fortunately, lower bounds exist and have been proved for linear fields (free quantum field theory), with few results for interacting models of QFT. In a class of quantum integrable models, on the level of one-particle states, we prove the existence of lower bounds for local averages of the energy density, establishing a first result for QFTs with interaction. In the massive Ising model, we can show a stronger bound that is independent of the particle number.
23 ottobre 2017 - Aula 713 - Seminario di MIDA (Sorrentino)

ore 11:00 - Francesca Ieva, Dipartimento di Matematica, Politecnico di Milano

"Nonparametric Inference for vital signs"

Abstract: The aim of the talk is to present an overview of nonparametric techniques for the statistical analysis of signals, based on depth measures and Spearman indexes. Adjusted functional boxplot for the identification of (multivariate) functional outliers and classification methods based on depths will be presented and discussed, together with applications to Electrocardiographic (ECG) signals.
6 ottobre 2017 - Aula 715 - Seminario di Teoria e Applicazioni delle Categorie (Rosolini)

ore 10:00-12:00 - Alessio Santamaria, University of Bath

"Reti di Petri come String Diagrams per trasformazioni dinaturali"

Abstract:
5 ottobre 2017 - Aula 705 - Seminario (Rogantin)

ore 9:00-14:00 - Pistone

4 ottobre 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - Shiv Prakash Patel (Ben-Gurion University of the Negev, Israel)

"Representations of p-adic groups"

Abstract: The p-adic groups are important in the study of automorphic forms and Langlands program. The representation theory of these groups is a bit different from those of real and complex groups. This happens because of the differences in the topology of real/complex numbers and p-adic numbers. We will review certain main concepts in this theory and consider the problem of restriction of an irreducible representation of a group to its certain subgroups. We give an example where it is possible to formulate the answers in terms of certain invariants attached to the representations involved, called epsilon factors. This is what is known as (local) Gross-Prasad conjectures. If time permits, we also consider an analogous question in the setting of covering groups

ore 15:00 -

"Finite numbers of initial ideals in non-Noetherian polynomial rings"

Abstract:
We will study ideal chains in the polynomial ring $R=KK[x_{i,j},|,1leq ileq c,jinNN]$ that are invariant under the action of the monoid $IInc(NN)$ of strictly increasing functions on $NN$, which acts on $R$ by shifting the second variable index. I will show that for every such ideal chain, the number of initial ideal chains with respect to term orders on $R$ that are compatible with the action of $IInc(NN)$ is finite. As a consequence of this, we will see that $IInc(NN)$-invariant ideals of $R$ have only finitely many initial ideals with respect to $IInc(NN)$-compatible term orders. The talk also addresses the question of how many such term orders exist. I will give a complete list of the $IInc(NN)$-compatible term orders for the case $c=1$ and show that there are infinitely many for $c >1$.
26 settembre 2017 - Aula 706 - Seminario di Conferenza Prof. Slawinski (De Mari)

ore 15:00-17:00 - Prof. Michael Slawinski (Memorial University of Newfoundland)

"Quantitative Seismology as Paradigm for Mathematical Physics"

Abstract: To infer physical properties of the Earth, quantitative seismology relies on abstract concepts that belong to the realm of mathematics. Consequently, mathematical entities and relations are Platonic analogies for physical properties and phenomena. In this seminar, we discuss such analogies and exemplify their capacity of explanation or prediction, as well as their intrinsic limitations.
25 settembre 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 14:30 - Francesco Polizzi (University of Calabria)

"A pair of rigid surfaces with $p_g=q=2$ and $K^2=8$ whose universal cover
is not the bidisk."

Abstract: We construct two complex-conjugated rigid surfaces with $p_g=q=2$ and
$K^2=8$, whose universal cover is not biholomorphic to the bidisk. We show
that these are the unique surfaces with these invariants and Albanese map
of degree $2$, apart a family of product-quotient surfaces constructed by
Penegini. This is a joint work with C. Rito and X. Roulleau.
25 settembre 2017 - 508 - Seminario di MIDA (Sorrentino)

ore 15:00-16:00 - Prof. Ratto

22 settembre 2017 - Aula 704 - Seminario di MIDA

ore 12:00-13:00 - Luca Bonaventura

21 settembre 2017 - Aula 713 - Seminario di Teoria dei Giochi (Pusillo)
12 settembre 2017 - Aula 713 - Seminario di mirror symmetry (Bartocci)
4 settembre 2017 - Aula 704 - Seminario di MIDA (Sorrentino)

ore 11:00-12:00 -

"Space weather at Mars: combining in-situ observations with particle transport models"

Abstract:
27 luglio 2017 - Aula 713 - Seminario (Bartocci)
11 luglio 2017 - Aula 706 - Seminario di PhD Colloquium (Pinamonti)

ore 14:30-16:00 - Prof. Martin Hyland (University of Cambridge)

"Logic hidden in Mathematics "

Abstract:
7 luglio 2017 - Aula 713 - Seminario di Teoria dei Numeri (Bettin)
5 luglio 2017 - Aula 714 - Seminario di MIDA (Sorrentino)

ore 11:15-12:30 - Massimo Vassalli, Istituto di Biofisica, CNR, Genova

"Exploiting label-free biomarkers for single cell phenotyping"

Abstract: Single living cells in our body experience a lifelong journey across different physiological and pathological states, proliferating to establish their condition (phenotype), or differentiating to switch to a new stage. A general challenge in bio-medical sensing is to assay the state of single cells through the identification of biochemical and biophysical markers. Due to their enhanced specificity, biochemical markers are by far the most adopted. Nevertheless, intrinsic biophysical markers (such as mechanical properties or geometrical descriptors of the cell) have recently attracted attention, in that they do not require costly labeling or sample preparation. Besides the experimental approach needed to achieve single cell resolution, these methods provide an interesting set of mathematical problems in terms of modeling, numerical handling of constitutive equations and data analysis. After a general overview, a specific focus will be posed on the so called quantitative phase microscopy (QPM), in which the phase of the electromagnetic field going through the sample is reconstructed to provide a 3D-like representation of the morphology. In particular, a non-interferometric approach based on the so called Transport of Intensity Equation (TIE) will be discussed, which is prone to a simple and cheap implementation based on the inversion of a partial differential equation.
3 luglio 2017 - Aula 716 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-16:00 - Davide Bolognini (University of Fribourg)

"BINOMIAL EDGE IDEALS OF BIPARTITE GRAPHS"

Abstract:
3 luglio 2017 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
28 giugno 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 14:30 -

"Moduli spaces of sheaves and irreducible symplectic varieties"

Abstract: Moduli spaces of sheaves on projective K3 surfaces have been intensively studied during the last three decades, proving to be a useful tool to produce example of irreducible symplectic manifolds: all the known examples of such manifolds can be obtained from some moduli spaces of sheaves over K3 surfaces (or over abelian surfaces). More precisely, if a moduli space of sheaves on a K3 surface is smooth, then it is an irreducible symplectic manifold. When the moduli space is singular, we have different phenomena: sometimes it has a resolution of the singularites which is an irreducible symplectic manifold; but more often this is not the case. In a recent joint work with Antonio Rapagnetta, still in progress, we show that all moduli spaces of sheaves on projective K3 surfaces are irreducible symplectic (singular) varieties, and we compute their Beauville form and the Hodge decomposition of their second integral cohomology, generalizing previous results in the smooth case of Mukai, O'Grady and Yoshioka.
22 giugno 2017 - Aula 713 - Seminario di Geometria algebrica (Penegini)

ore 14:00 - A. Ottazzi (UNSW)

ore 15:00 - Luca Ugaglia (University of Palermo)

22 giugno 2017 - Aula 705 - Seminario di PhD Colloquia (Bruno)

ore 15:00-17:00 -

"On the maximal operator for a normal Ornstein-Uhlenbeck semigroup"

Abstract:
21 giugno 2017 - Aula 706 - Seminario (Rosolini)

ore 14:00 - Prof. John Baez

"Applied Category Theory"

Abstract: Nature and the world of human technology are full of networks. People like to draw diagrams of networks: flow charts, electrical circuit diagrams, signal-flow graphs, Bayesian networks, Feynman diagrams and the like. Mathematically minded people know that in principle these diagrams fit into a common framework: category theory. But we are still far from a unified theory of networks.
21 giugno 2017 - Aula 706 - Seminario (Rosolini)

ore 11:00 - Prof. John Baez

""

Abstract:
21 giugno 2017 - Aula 508 - Seminario (Rosolini)
16 giugno 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 14:00 - Gilberto Bini (University of Milan)

"Calabi-Yau varieties in strict sense"

Abstract: Calabi-Yau varieties in strict sense are studied by algebraic geometers and arithmetic geometers, as well as by differential geometers. Unlike other varieties with trivial canonical bundle, quite a few examples are known, but not so many questions about their general properties have been tacked so far.
In this talk, we will present some contributions to the state of the art of research on these varieties. On the one hand, we will show new examples, some found in collaboration with Filippo F. Favale (Unitn) and others with Matteo Penegini (Unige). On the other hand, we will answer a question about their geometric properties and we will comment on a new result in collaboration with Filippo F. Favale (Unitn) concerning a countable family of log Calabi-Yau varieties for which the set of corresponding Euler characteristics is not bounded from above.
16 giugno 2017 - Aula 705 - Seminario di MIDA (Sorrentino)

ore 12:00-13:00 - Ezio Venturino, Dipartimento di Matematica, Torino

"An overview of recent models in mathematical biology"

Abstract:
15 giugno 2017 - Aula 713 - Seminario di Teoria dei Numeri (Bettin)
14 giugno 2017 - Aula 713 - Seminario di Algebra e Geometria (Bigatti)

ore 16:00 - A. Bigatti

""

Abstract:
7 giugno 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 15:30 - Zeljka Stojanac (Aachen university)

"Low-rank tensor recovery"

Abstract:
1 giugno 2017 - Aula 704 - Seminario (Perelli)

ore 16:00-17:00 - prof. Zannier

31 maggio 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 13:30-15:30 -

"A variation on a theme of Faber and Fulton"

Abstract: In this talk we study the geometry of GIT con gurations of n ordered points on P1 both from the the birational and the biregular viewpoint. In particular, we prove that any extremal ray of the Mori cone of effective curves of the quotient (P1)^n//PGL(2), taken with the symmetric polarization, is generated by a one dimensional boundary stratum of the moduli space. Furthermore, we develop some technical machinery that we use to compute its group of automorphisms. (joint work with A.Massarenti)
31 maggio 2017 - Aula 714 - Seminario di seminari dottorandi (Bruno)
30 maggio 2017 - Aula 716 - Seminario di Machine Learning (De Vito)

ore 15:00-16:00 - Andreas Maurer

"A second order look at stability and generalisation"

Abstract: Using differentiability assumptions on the loss function and a concentration inequality for bounded second-order differences it is shown, that the generalization error for classification with L2 regularisation obeys a Bernstein-type inequality and has a sub-Gaussian upper bound, modulo terms of order 1/n.
29 maggio 2017 - Aula 714 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 -

"Moduli space of curves, tautological relations and integrable systems"

Abstract:
16 maggio 2017 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30 - Prof. J. Brudern (Univ. Gottingen)

"Artin's conjecture: a new approach and new cases"

Abstract: Joint work with Olivier Robert provides a new approach to Artin's conjecture in diophantine analysis. We propose a new diagonalisation procedure that allows us to bring in the combinatorial theory of p-groups. As a first application, we are able to establish Artin's conjecture for linear slices of diagonal hypersurfaces.
16 maggio 2017 - Aula 704 - Seminario di Teoria dei Giochi (Pusillo)

ore 14:30 - L. Spada

"I geni: abili giocatori. Tentativo di scoprirne le carte"

15 maggio 2017 - Aula 713 - Seminario di Storia della Matematica (Bartocci)
11 maggio 2017 - Aula 706 - Seminario di PhD Colloquium (Pinamonti)

ore 14:30-16:00 - E. Delucchi

"Fundamental polytopes of metric trees via hyperplane arrangements"

Abstract: The problem of a combinatorial classification of finite metric spaces via their fundamental polytopes was suggested by Vershik in 2010, but to date the structure of these polytopes (even their face numbers) remains largely unknown. In this talk, based on joint work with Linard Hoessly, I will explain how to associate a hyperplane arrangement to every split pseudometric and how to use its combinatorics in order to compute the face numbers of fundamental polytopes and Lipschitz polytopes of tree-like metrics. I will discuss how to apply our results to specific examples and, time permitting, I will briefly comment on the potential of our model beyond tree-like metrics. I will introduce all the mentioned mathematical objects so that no specific prerequisites should be required - hence all graduate students are welcome!
10 maggio 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 15:00 - E. Delucchi (University of Fribourg)

"Toric arrangements and group actions on semimatroids"

Abstract: Recent work of De Concini, Procesi and Vergne on vector partition functions gave a fresh impulse to the study of toric arrangements from an algebraic, topological and combinatorial point of view. In this context, which can be seen as a step beyond the successful theory of linear arrangements (a.k.a. arrangements of hyperplanes), many new combinatorial structures have recently appeared in the literature, each tailored to one of the different facets of the subject. Yet, a comprehensive combinatorial framework is lacking.
In this talk I will gently introduce toric arrangements and, as combinatorial structure unifying linear, toric and elliptic arrangements, I will propose the study of group actions on semimatroids and of related polynomial invariants. Together with recent results, I will outline some new open problems brought to the fore by the development of the theory.
9 maggio 2017 - Aula 704 - Seminario di Teoria dei Giochi (Pusillo)

ore 14:30 - G. Gnecco (IMT-Lucca)

"Ottimizzazione a squadra e applicazioni"

9 maggio 2017 - Aula 716 - Seminario (Pinamonti)

ore 10:00-11:30 -

"Gauge-invariant observables in perturbative quantum gravity"

Abstract: It is well known that the diffeomorphism invariance of gravitational theories makes it impossible to define local and gauge-invariant observables in perturbative (quantum) gravity, except at linear order. While in flat space on can study the S-Matrix, which is a gauge-invariant global observable, no analogue exists in a general curved space. Relational observables (i.e., the value of one field at the point where a second field has a prescribed value) are natural candidates for observables in (quantum) gravity, but they are not local when constructed around flat space or around a cosmological (FLRW) background spacetime due to the high symmetry of the latter.
We present two different approaches to this problem: a) correlation functions at fixed geodesic distance, and b) a construction of invariant coordinates, for which explicit and fully renormalized results for one-graviton-loop corrections to two- point functions and coupling constants have been obtained.
6 aprile 2017 - Aula 713 - Seminario di Algebra e Geometria (Penegini)

ore 14:00-16:00 - Prof. Lidia Stoppino

"New Severi inequlities for irregular varieties"

6 aprile 2017 - Aula 716 - Seminario di seminari dottorandi (Bruno)
28 marzo 2017 - Aula 508 - Seminario di MIDA (Sorrentino)

ore 11:00-12:00 - Simona Schiavi, DINOGMI

"Introduction to diffusion magnetic resonance imaging (dMRI) and a new mathematical model"

Abstract:
22 marzo 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Kazuho Ozeki (Yamaguchi University)

"The structure of the Sally module of integrally closed ideals"

Abstract:
16 marzo 2017 - Aula 706 - Seminario di PhD Colloquia (Pinamonti)

ore 15:00-17:00 - Professor Mathias Schulze TU Kaiserslautern (Germany)

"Logartihmic differential forms and residues"

Abstract: Logarithmic differential forms first appeared along normal crossing divisors in Deligne's construction of the mixed Hodge structure. They were later generalized by Kyoji Saito along reduced hypersurfaces in his study of the Gauss-Manin connection on base space of the versal deformation of isolated hypersurface singularities. The discriminant in such a base space was the first prominent example of a so-called free divisor. We give a gentle introduction to this topic mostly based on examples and simple calculations. Then we explain a relation between logarithmic residues and normal crossing divisors. We end with an outlook on recent generalizations of the notion of free divisor to higher codimension.
15 marzo 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - Klaus Altmann (FU Berlin)

"Q-Gorenstein deformations of toric singularities (joint work with J'anos Koll'ar)"

Abstract: We recall how toric deformations can be understood via the decomposition of certain polytopes into Minkowski summands.
Together with a combinatorial description of the vector space of the infinitesimal deformations T1, this gives rise to a natural understanding of the Kodaira-Spencer map. Then, we focus on two-dimensional quotient singularities and compare Q-Gorenstein deformations in the global and in the infinitesimal level. We will see that the corresponding functor is obstructed and hence will replace it by gadgets we call qG-deformations.

ore 15:00 - Michele Torielli (Hokkaido University)

"Freeness of certain sign graphic arrangements"

Abstract: In this talk, firstly, I will describe the connection between signed graphs and subarrangements of Coxeter arrangements of the type B. Then I will discuss some partial results for the characterization of freeness for this type of subarrangements. This is a joint work with D. Suyama and S. Tsujie
9 marzo 2017 - Aula 713 - Seminario di Prof. Kaczorowski (Perelli)

ore 11:00-12:00 - Prof. Kaczorowski

9 marzo 2017 - Aula 705 - Seminario di Teoria e Applicazioni delle Categorie (Rosolini)

ore 17:00 - Jacopo Emmenegger

"Exact completions and constructive theories of sets"

Abstract:
9 marzo 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Thomas Kahle (University of Magdeburg)

"Finding binomials in polynomial ideals"

Abstract: We describe an algorithm which finds binomials in a given
ideal in a polynomial ring and in particular decides whether binomials
exist in I at all. These binomials can be well hidden. For example, the
lowest degree of a binomial cannot be bounded as a function of the
number of indeterminates, the degree of the generators, or the
Catelnuovo-Mumford regularity. We approach the detection problem by
reduction to the Artinian case using tropical geometry. The Artinian
case is solved with algorithms from computational number theory
6 marzo 2017 - Aula 714 - Seminario di seminari dottorandi (Bruno)
2 marzo 2017 - Aula 706 - Seminario di Machine Learning (De Vito)

ore 15:00-16:00 -

1 marzo 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Roberto Pignatelli (University of Trento)

"On semi-isogenous mixed surfaces"

Abstract: In the last 15 years several authors have studied the complex algebraic surfaces that are birational to the quotient of a product of two curves by the action of a finite group. In these years this class of surfaces has proved to be very prolific of interesting examples, whose constructions answered a certain number of open questions.
The theory developped in these 15 years started from the case when the action is free (the surfaces isogenous to a product), to be extended to the case when the action is supposed to be free out of a finite set of points.
The only attempt to remove this assumption including in the theory, for example, the symmetric product of a curve, is due to Cancian and Frapporti who introduced the surfaces in the title, in a paper (with the same name) appeared at the end of 2015 on arxiv.
I will recall their definitions and results and then I will enter in the detail of one of their construction, giving a geometric description of one of their family and then discussing its deformation theory (joint work with F. Polizzi). If time permits, I will also mention some recent unpublished progress of this new theory.
28 febbraio 2017 - Aula 706 - Seminario di Machine Learning (De Vito)

ore 15:00-16:00 - Aymeric Dieuleveut

"Harder, Better, Faster, Stronger Convergence Rates for Least-Squares Regression"

15 febbraio 2017 - Aula 706 - Seminario di (De Vito)

ore 15:00-16:00 - Ilaria Giulini

"Data driven estimation of the Laplace-Beltrami operator"

Abstract: Approximations of the Laplace-Beltrami operator on manifolds through graph Laplacians have become popular tools in data analysis and machine learning. These discretized operators usually depend on bandwidth parameters whose tuning remains a theoretical and practical problem. We address this problem for the unnormalized graph Laplacian by establishing an oracle inequality that opens the door to a well-founded data-driven procedure for the bandwidth selection. Our approach relies on recent results by Lacour, Massart, Rivoirard (2016) on the so called Lepski method.
1 febbraio 2017 - Aula 706 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30-16:00 - C. Pedrini

"ON THE RATIONALITY OF A CUBIC FOURFOLD"

Abstract: Let X be a cubic fourfold in P5C. All known cubic fourfolds are rational while the very general one is conjecturally irrational.We prove that, assuming the Hodge conjecture for the product SS, where S is a complex surface, and the nite dimensionality of the Chow motive h(S), there are at most a countable number of decomposable integral polarized Hodge structures, arising from the bers of a family f : S ! B of smooth projective surfaces. According to the results by A.Auel, C.Bohning and H.C.
Graf von Bothmer, this is related to a conjecture proving the irrationality of a very general X.
25 gennaio 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Amir Mafi (University of Kurdistan Sanandaj, Iran)

"RESULTS ON STABILITY OF POWERS OF IDEALS OVER REGULAR LOCAL RINGS OF SMALL DIMENSION"

Abstract: Let (R;m) be a regular local ring with dimR  3 or a polynomial ring R = k[x; y; z] over a eld k and let I be a graded ideal of R. We show that
astab(I) = dstab(I). In addition, we give examples which show that this equality does not hold for rings of dimension bigger than 3. Furthermore if R = k[x; y; z; u], then for any non-negative integer c there exists two ideals I and J of R such that astab(I) &#1048576; dstab(I)  c and dstab(J) &#1048576; astab(J)  c.
24 gennaio 2017 - Aula 713 - Seminario di seminari dottorandi (Bruno)
19 gennaio 2017 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 11:00-13:00 - J. Rafael Sendra (Universidad de Alcala`, Madrid)

"Radical Varieties"

Abstract: In many applications, where geometric constructions appear, parametrizations of the geometric objects are used. In practice, when the geometric entities are algebraic,
the varieties are assumed to be rational, and hence representable by means of rational functions. This is a limitation of the feasibility of the application, since the class
of rational varieties may turn to be small for the practical purposes. To overcome this difficulty one may use approximations or, alternatively, enlarge the family of
functions allowed to be used in the parametric representation of the geometric object, for instance by introducing radicals of polynomials. This is the theoretical frame of this talk. In this talk, we will introduce the notion of rational parametrization as well as the associated concept of rational variety. Additionally, we will introduce a second, auxiliary, variety,
named the tower variety. In addition, we will study some of their fundamental properties. From the computational point of view, we will present algorithms for implicitizing
radical varieties and, for the particular cases of curves and surfaces, we will also present reparametrization and parametrization algorithms.
21 dicembre 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - Anjan Gupta (University of Genoa)

"Detecting Koszulness and related homological properties from the algebra structure of Koszul homology"

Abstract: In this talk, we discuss the relationship between the multiplicative structure of Koszul homologies and the property that R is a Koszul algebra in the setting of local rings; we show that certain conditions on the multiplicative structure of Koszul homology imply strong homological properties, such as existence of certain Golod homomorphisms, leading to explicit computations of Poincare &#769; series. As an application, we prove that the Poincare &#769; series of all finitely generated modules over a stretched Cohen-Macaulay local ring are rational, sharing a common denominator. This is a joint work with Amanda Croll, Roger Dellaca, Justin Hoffmeier, Vivek Mukundan, Denise Rangel Tracy, Liana M. Sega, Gabriel Sosa and Peder Thompson

ore 15:00 - Anurag Singh (University of Utah)

"Magic squares"

Abstract:
15 dicembre 2016 - Aula 715 - Seminario di seminari dottorandi (Bruno)
14 dicembre 2016 - Aula 715 - Seminario di Fisica Matematica (Pinamonti)

ore 14:30-15:30 -

"Is there a natural state for Abelian Chern-Simons theory?"

Abstract: We give a simple proof that Abelian Chern-Simons theory, described as a functor from oriented surfaces to C*-algebras, does not admit a natural state. Non-existence of natural states is hence not only an issue for dynamical quantum field theories on Lorentzian manifolds, but also for topological quantum field theories formulated in the algebraic approach.
13 dicembre 2016 - Aula 706 - Seminario di PhD Colloquia (Pinamonti)

ore 15:00 - Prof. L. Parkkonen, Aalto University, Department of Neuroscience and Biomedical Engineering (Finland)

"Machine-learning the brain"

Abstract:
5 dicembre 2016 - Aula 705 - Seminario di MIDA (Sorrentino)

ore 16:00-17:00 - Claudio Estatico, DIMA

"Regularization methods in variable exponent Lebesgue spaces"

5 dicembre 2016 - Aula 716 - Seminario di Teoria dei Giochi e scelte strategiche (Pusillo)
2 dicembre 2016 - Aula 714 - Seminario di Teoria delle Categorie (Rosolini)
29 novembre 2016 - Aula 715 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-16:00 - Ulrich v. d. Ohe (University of Osnabrueck)

""

Abstract:
24 novembre 2016 - Aula 705 - Seminario di studenti IGS (Beltrametti)
15 novembre 2016 - Aula 715 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-16:00 - L. Robbiano (University of Genoa)

"Duality in Zero-Dimensional Affine Algebras"

9 novembre 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - L. Robbiano (University of Genoa)

"Primary Decomposition in Zero-Dimensional Affine Algebras"

8 novembre 2016 - Aula 716 - Seminario di PhD Seminar (Bruno)

ore 11:00 - Sepehr Jafari

"From algebraic geometry to homological algebra"

Giamila Zaghloul

"Converse theorems for modular L-functions"

3 novembre 2016 - - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Martina Juhnke-Kubitzke (University of Osnabrueck)

"A generalized lower bound theorem for balanced manifolds"

Abstract: A classical question in the combinatorics of simplicial complexes asks for lower bounds of their face numbers. In this talk, we are interested in balanced simplicial complex.
Recall that a simplicial complex of dimension $d&#8722;1$ is said to be balanced if its graph is $d$-colorable. We prove lower bounds for the $h$-vectors of balanced triangulations of closed homology manifolds and balanced triangulations of orientable homology manifolds with boundary under an additional assumption that all proper links of these triangulations have the weak Lefschetz property. As a corollary, we show that if $Delta$ is an arbitrary balanced triangulation of any closed homology manifold of dimension $d&#8722;1geq 3$, then
$2h_2(Delta)-(d-1)h_1(Delta)geq 4inom{d}{2}(eta_1(Delta)-eta_0(Delta)), thus verifying a conjecture by Klee and Novik. To prove these results we develop the theory of flag h&#8242;&#8242;-vectors.
This is joint work with Satoshi Murai, Isabella Novik and Connor Sawaske
3 novembre 2016 - Aula 713 - Seminario (Fassino)

ore 14:00-16:00 - Prof. Pistone

"Geometries of the multivariate Gaussian model and the multivariate Gaussian graphical model: exponential, mixture, Wasserstein"

Abstract:
2 novembre 2016 - Aula 706 - Seminario di Algebra e Geometria

"prova"

Abstract: provaprova
2 novembre 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Alexandru Constantinescu (University of Genoa)

"Deformations of Monomial Ideals"

Abstract: This talk is an overview of my INdAM-funded project which I will work on at DIMA over the next two years. The over-arching goal is to use the combinatorial nature of monomial ideals to gain knowledge about their abstract deformations. These boil down to flat families. We are interested in isomorphism classes of such families, and these are controlled by cotangent functors. Just as the first and second derivative have a geometric interpretation, the first two cotangent modules are
enough to control deformations. Monomial ideals have two advantages in this setting: we know their syzygy modules, and their multigrading gets carried over to the cotangent modules. I will give a brief overview of the work done by Altmann and Christophersen on deformations of Stanley-Reisner schemes. For algebraic geometry, this is of interest because some classical varieties (Calabi-Yau, Abelian, Enriques surfaces) degenerate to special types of Stanley-Reisner schemes of combinatorial manifolds (respectively homotopy spheres, tori, triangulations of the real projective plane). I will then present some combinatorial and algebraic problems where deformations could be used to develop a new approach
27 ottobre 2016 - Aula 704 - Seminario di MIDA (Sorrentino)

ore 16:30 - Vittorio Latorre, Department of Computer, Control and Management Engineering, Sapienza University of Rome

Abstract: In this seminar we talk about the Edge preserving functions in image recognition, regression and classification. Edge preserving functions are non-convex function used to measure the similarity between two data points. They have the propriety to put together samples with strong similarities and separate samples that are different from each other, giving to the obtained model good generalization capabilities. The main drawback of these functions is that they are generally non-convex, giving rise to difficult non-convex optimization problems.

To ameliorate this issue ,in literature the Half-quadratic reformulation has been employed. This reformulation simplifies the problem, making it quadratic is a subset of variables, allowing the use of simpler optimization strategies.

With the use of duality in non-convex optimization, the so called Canonical Duality Theory, we better explore the theoretical proprieties of the half-quadratic formulation, showing that there is a one to one relation between the stationary points of the original problem and the Half-quadratic reformulation. Furthermore we propose an efficient algorithm that exploits both the half quadratic nature of the problem and the results from the Canonical Duality Theory with application to a real world regression problem.
27 ottobre 2016 - Aula 705 - Seminario di PhD Colloquia (Pinamonti)

ore 14:30-16:00 -

"The Pseudodifferential calculus and Hadamard states"

Abstract: In this talk we will describe the use of pseudodifferential calculus to construct and study Hadamard states for free Klein-Gordon fields on globally hyperbolic spacetimes.
Pseudodifferential calculus on manifolds is a standard tool of microlocal analysis which actually predates the notion of wavefront set. We will give a brief description of various pseudodifferential calculi on manifolds and relate the construction of Hadamard states done with Michal Wrochna and Omar Oulghazi with the well-known method of the mode expansion in the case of cosmological spacetimes. We will also give a new proof of the Hadamard property of the Hartle-Hawking-Israel state for static bifircate Killing horizons due to Sanders.
26 ottobre 2016 - Aula 706 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00-15:00 - Gabriele Balletti (Stockholm University)

"Make Ehrhart Theory great again"

Abstract: In 1962 Ehrhart proved that the number of lattice points in integer dilations of a lattice polytope is described by a polynomial (the Ehrhart polynomial). It has been then natural to wonder which polynomials are Ehrhart polynomials. Although some progress has been made, this question is still widely open today. In this talk I will introduce this beautiful theory from scratch, mention some small steps we have taken and suggest some possible ways to approach the problem.
24 ottobre 2016 - Aula 715 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30-15:30 - prof. Bruedern

20 ottobre 2016 - Aula 509 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - L. Robbiano

"Computational Linear and Commutative Algebra
M. Kreuzer - L. Robbiano Springer 2016"

17 ottobre 2016 - Aula 716 - Seminario di Teoria delle Categorie (Rosolini)

ore 14:00-17:00 - F. Pasquali

"Sottocategorie di EQU"

17 ottobre 2016 - Aula 713 - Seminario di Teoria delle Categorie (Rosolini)

ore 11:00-13:00 - F. Pasquali

"Sottocategorie di EQU"

6 ottobre 2016 - Aula 509 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30-17:00 - A. Conca

"A remark on regularity"

Abstract: During the talk we will discuss on the behavior of the Castelnuovo-Mumford regularity for products of powers of polynomial ideals.
28 settembre 2016 - Aula 715 - Seminario di Analisi Armonica (Carbonaro)
22 settembre 2016 - Aula 706 - Seminario di PhD Colloquia (Pinamonti)

ore 14:30-16:00 -

"The Taylor formula of implied volatility"

Abstract: In a model driven by a multi-dimensional local diffusion, we study the behaviour of implied volatility
IV and its derivatives with respect to log-strike k and maturity T near expiry and at the money. We recover
explicit limits of the derivatives of the IV for (T, x &#8722; k) approaching the origin within the parabolic region
|x &#8722; k| &#8804; &#955;&#8730;T, with x denoting the spot log-price of the underlying asset and where &#955; is a positive and arbitrarily
large constant. Such limits yield the exact Taylor formula for implied volatility within the parabola
|x&#8722;k| &#8804; &#955;&#8730;T. In order to include important models of interest in mathematical finance, e.g. Heston, CEV,
SABR, the analysis is carried out under the weak assumption that the infinitesimal generator of the diffusion
is only locally elliptic.
21 settembre 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Richard Sieg (University of Osnabrueck)

"Representations of Hilbert series in Normaliz"

Abstract: One of the major computation goals in Normaliz is the Hilbert Series of an affine monoid, that is, the generating function for counting elements in each degree. We will discuss the current calculation and representation of this series in Normaliz. Next we will present a new form which is compact and allows for a combinatorial interpretation. This form is attained by calculating the degrees of a homogeneous system of parameters for the monoid algebra and we will present and discuss an algorithm to compute them.
19 settembre 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)
14 settembre 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Richard Sieg (University of Osnabrueck)

"The subdivision of large simplicial cones in Normaliz"

Abstract: Normaliz is an open-source software for computations in rational cones and affine monoids. The two main computational goals are (1) the Hilbert Basis, a minimal generating system of the monoid of lattice points of a given cone; (2) the Hilbert (or Ehrhart) series, the generating function of the degree wise lattice point enumerator. Normaliz offers a rich variety of input types for cones and lattices. It can be accessed from several computer algebra systems, and provides a C++ class library for use in other software.

The primal algorithm of Normaliz is based on triangulations. The complexity of the algorithm is determined by the combinatorial complexity of the triangulation and the arithmetical complexity of the resulting simplicial cones, measured by the determinant of the generating matrix. Normaliz can cope with very large triangulations due to its pyramid decomposition algorithm, but large determinants are a severe problem, despite of the parallelized computation of a single large simplicial cone.

An often successful way out is the (iterated) subdivision of large simplicial cones by stellar subdivisions into simplicial subcones whose determinant sum is significantly smaller than the original determinant. At present Normaliz offers two methods for finding good subdividing vectors. The first approach uses techniques from integer programming. For this purpose we access the integer programming solver from SCIP. The second approach approximates the critical simplicial cone from the outside by a cone with smaller generators and tries to find good subdividing vectors among the lattice points of the approximating cone.
12 settembre 2016 - Aula 715 - Seminario (Riccomagno)

ore 15:30 -

"Bayesian semiparametric multivariate models for extreme exceedances"

Abstract: Interest on extremal events generally involves the joint study of many concomitant variables, as for instance wave height and surge. We build on previous work which specifically accounted for marginal exceedances over a high, unknown threshold, by combining it with flexible families of copulae. This approach allows for the detection of specific patterns of dependence be them extremal or not. Attention is also devoted to the ascertainment of asymptotic independence, where standard multivariate extreme value theory is not applicable. Estimation of higher quantiles and other quantities of interest is performed both marginally and conditionally via MCMC algorithms. Our approach is evaluated through a series of simulations and is applied to real data sets

ore 16:30 -

""

Abstract: Over the last decades several natural history studies on primary progressive MS (PPMS) patients were reported from international registries. In this population a consistent heterogeneity was observed in the rate of disability accumulation, as time to reach the milestone of Expanded Disability Status Scale (EDSS) 6 ranged between 7 and 14 years from onset.
Objectives. To identify subgroups of PPMS patients with similar longitudinal trajectories of EDSS over time.
Methods. All PPMS patients collected within the MSBase international registry, who had their first EDSS assessment within 5 years from onset were included in the analysis. Longitudinal EDSS scores were modelled by a latent class mixed model (LCMM), using a nonlinear function of time from onset. LCMM is an advanced statistical approach that models heterogeneity between patients by classifying them into unobserved groups (latent classes) showing similar characteristics.
Results. A total of 853 PPMS (51.7% females) from 24 countries with a mean age at onset of 42.4 yrs (SD: 10.8 yrs), a median baseline EDSS of 4 (IQR: 2.5-5.5) and 2.4 yrs of disease duration (SD: 1.5 yrs) were included. LCMM detected 3 different subgroups of patients with a mild (n=143 ;16.8%), moderate (n=378; 44.3%) or severe (n=332; 38.9%) disability trajectory. Median time to EDSS 4 was 14, 5 and 3.7 years respectively, for the 3 groups. The probability of reaching EDSS 6 at 10 years was 0%, 46.5% and 83.1% respectively. Using this modelling approach it is possible to predict the future disease course of a subject with PPMS using early EDSS assessments. Using only 1 year of EDSS monitoring 73% of patients are correctly classified in their disability trajectory group (mild, moderate or severe); after 3 years this proportion increases to 87% and after 5 years it reaches 92%.
Conclusions. Using long-term observations and an LCMM modelling approach, it is possible to build a dynamic model, to predict the future disability trajectory of newly diagnosed PPMS patients. In the design of future clinical trials in PPMS, using time to reach disability milestones as the primary endpoint, the existence of heterogeneous classes of patients should be considered
20 luglio 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 13:00 - Hop Nguyen (University of Genova)

"Powers of sums and their homological invariants"

Abstract: Let R, S be standard graded algebras over a field k, and I, J be homogeneous ideals contained in R, S, resp. We consider the sum P of I and J in the tensor product of R and S over k. Various homological invariants of the individual and large enough powers of P can be computed in terms of the data of I and J. The method hinges on the smallness property of maps between consecutive powers of I and J. This is joint work with T. Vu.

ore 14:00 - Alessandro De Stefani (KTH, Stockholm)

"Globalized Hilbert-Kunz multiplicity and F-signature"

Abstract: The Hilbert-Kunz multiplicity and the F-signature are two important invariants of a local ring of prime characteristic. They are subtly connected with the theory of singularities, and often provide a good measure of how ill-behaved a ring can be. We will survey some classical results on these invariants, and show how to extend these notions to rings that are not necessarily local, in a way that still detects meaningful information about the ring. This is joint work with Thomas Polstra and Yongwei Yao.
15 luglio 2016 - Aula 713 - Seminario (Sasso)

ore 14:00 - Adam Nowak (Institute of Mathematics Polish Academy of Sciences)

"Potential operators associated with various orthogonal expansions"

Abstract: We overview our recent results concerning counterparts of the classical Riesz and Bessel potentials in the settings of Jacobi, Hermite, special Hermite, Laguerre, Dunkl-Laguerre, discrete and continuous Fourier-Bessel, and Dunkl-Fourier-Bessel expansions. The results, obtained in collaboration with K. Stempak and L. Roncal, embrace sharp estimates for the potential kernels and complete descriptions of Lp-Lq mapping properties of the potential operators. The latter may be regarded as sharp analogues of the celebrated Hardy-Littlewood-Sobolev theorem in the above mentioned contexts.
14 luglio 2016 - Aula 705 - Seminario (De Vito)

ore 15:00-16:00 - S. Vigogna Dep. of Math. (Duke University, Durham, USA)

"Learning Adaptive Multiscale Approximations to Functions of Low-Dimensional Sets "

Abstract: We study the regression problem on manifolds embedded in high dimension. Given a finite number of high-dimensional samples drawn from an unknown probability distribution whose marginal support lies on an unknown submanifold of (much) lower dimension, we construct a universal estimator for the regression function.
Our estimator approximates the underlying function in a multiscale fashion, adapting to the intrinsic geometry and local regularity. We show convergence both in probability and in expectation, providing explicit rates for the finite sample performance. The approximation error is proven to be optimal (up to logarithmic factors) on a wide class of smoothness spaces, and is independent of the ambient dimension. All algorithms have complexity O(n log(n)), with constants scaling only linearly on the ambient dimension
6 luglio 2016 - Aula 705 - Seminario di Analisi Armonica (De Vito)

ore 15:00-16:00 - Jens Christensen (Department of Mathematics, Colgate University, USA)

"Atomic decomposition of Bergman spaces on bounded symmetric domains"

Abstract: We will show how representation theory and sampling theory combine to provide atomic decompositions for Bergman spaces on bounded symmetric domains. We will mostly focus on the unit ball and only mention some preliminary results on general bounded symmetric domains if time permits.
This is joint work with Karlheinz Grochenig and Gestur Olafsson in the area of coorbit theory, and it uses representation theory to provide new results in complex analysis.
1 luglio 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

Pagina web

ore 14:30 - Indranath Sengupta (IIT Gandhinagar)

30 giugno 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - Sara Maloni (Brown University)

"Polyhedra inscribed in quadrics and their geometry"

Abstract: In 1832 Steiner asked for a characterization of polyhedra which can be inscribed in quadrics. In 1992 Rivin answered in the case of the sphere, using hyperbolic geometry. In this talk, I will describe the complete answer to Steiner's question, which involves the study of interesting analogues of hyperbolic geometry including anti de Sitter geometry. Time permitting, we will also discuss future directions in the study of convex hyperbolic and anti de Sitter manifolds.
(This is joint work with J. Danciger and J.-M. Schlenker.)
28 giugno 2016 - Aula 704 - Seminario di Analisi Armonica (De Vito)

ore 15:00-16:00 - V.S. Varadarajan - UCLA Department of Mathematics, Los Angeles

"What is supergeometry and why should a mathematician care about it?"

Abstract: Supergeometry is a new kind of geometry which is a profound extension of
geometry as we know it, discovered by physicists around the 1970s, in their
quest for a quantum field theory free of divergences. It suggests that the local
structure of spacetime is startlingly different from what mathematicians from
Euclid to Grothendieck had imagined. The one exception was Riemann, who,
in his famous 1854 inaugural talk, speculated that the local structure of space
need not be that of a manifold but has to be determined by physics.

In this talk, which does not require much technical background except at a few
places, I shall trace the evolution of geometry and try to show why supergeometry i
s a natural continuation of this evolution, what are the consequences of the assumption
that spacetime is supergeometric, and show that it deserves the attention of even
mathematicians who have no interest in the natural world.
27 giugno 2016 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
15 giugno 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Gunnar Floystad (University of Bergen)

"Letterplace ideals from posets: A large class of ideals with unusually nice properties"

Abstract: To any poset P and natural number n we associate a monomial ideal L(n,P), called a letterplace ideal, in the polynomial ring $k[x_{p,i}]_{p in P, 1leq i leq n}$.
Its Alexander dual ideal L(P,n), we call a co-letterplace ideal.

More generally any poset ideal $gIsubseteq Hom(P,[n])$ (the codomain
[n] is the totally ordered set on n elements), gives rise to an ideal
$L(gI) subseteq L(P,n)$ and the Alexander dual $L(gI)^A supseteq L(n,P)$.

We inform on the omnipresence of these ideals, their resolutions, deformations, and how they give rise to a class of triangulations of spheres comprehensively generalizing Bier spheres.
14 giugno 2016 - Aula 713 - Seminario di Teoria dei Numeri (Bettin)
14 giugno 2016 - Aula 706 - Seminario di PhD Colloquia (Pinamonti)

ore 14:30-16:00 -

"The interplay between combinatorics and commtative algebra"

Abstract: Many combinatorial objects can be coded into a graph, or more generally a simplicial complex X on n vertices. To X there is a standard way of associating a quotient ring k[X] of the polynomial ring k[x_1,x_2,...,x_n]. The ring k[X] is called the Stanley-Reisner ring of X. This opens up the arsenal of algebra to study combinatorial objects.

This gives a rich interplay between algebra and combinatorics. We give a glimpse of methods and results in this area. We end with a surprising combinatorial discovery which dropped out of this algebraic machinery, obtained jointly with Alessio D'Ali and Amin Nematbakhsh.
9 giugno 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 13:00 - Alessio Sammartano (University of Purdue)

"Blowup algebras of rational normal scrolls"

Abstract: The Rees ring and the fiber ring of a polynomial ideal I, also known as the blowup algebras of I, play an important role in commutative algebra and algebraic geometry. A central problem is to describe the implicit defining equations of these algebras. I will report on some work in progress towards the solution of this problem for the case of ideals of rational normal scrolls. This extends classical results of Conca-Herzog-Valla and more recent ones of Bruns-Conca-Varbaro.

ore 14:00 - Bruno Benedetti (University of Miami)

"INDUCTIVE CONSTRUCTIONS OF 3-BALLS WITHOUT INTERIOR VERTICES"

Abstract: We will see a few ways to recursively construct triangulated 3-balls
without interior vertices, starting from a bunch of tetrahedra. These
methods are motivated by some important convergence issues in discrete
quantum gravity. If time permits, I will show how to tackle a conjecture
from 1995 by Mogami.
7 giugno 2016 - Aula 713 - Seminario di Teoria dei Numeri (Bettin)
27 maggio 2016 - Aula 713 - Seminario di Teoria dei Giochi (Pusillo)
27 maggio 2016 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
26 maggio 2016 - Aula 716 - Seminario di Teoria dei Giochi (Pusillo)
26 maggio 2016 - Aula 704 - Seminario di Seminario dottorandi (Sommariva)
25 maggio 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - Luigi Ferraro (University of Nebraska)

"Intersezioni complete con azione del gruppo simmetrico"

ore 15:00 - Federico Galetto (McMaster University)

"Intersezioni complete con azione del gruppo simmetrico"

Abstract:
23 maggio 2016 - Aula 713 - Seminario di Ananlisi Armonica (Mauceri)

ore 15:30-16:30 - Prof. Michael Cowling (University of South Wales)

"Sub-Finsler geometry and finite propagation speed"

Abstract: This is an account of joint work with Alessio Martini.
Given a first order formally self-adjoint differential operator $D$ on vector bundles over a manifold $M$, we associate to $D$ a natural sub-Finsler distance.
Under reasonable assumptions on $D$ (or on the distance), we show finite propagation speed estimates for the associated wave-type operator, and self-adjointness for $D$ itself
18 maggio 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - S. Scaramuccia

"MULTIDIMENSIONAL PERSISTENT HOMOLOGY: the algebraic setting"

Abstract: The aim of the talk is to present the algebraic setting of persistent homology in its single and multidimensional versions. In the single case, persistent homology comes associated with a graded module over the polynomial ring in a single indeterminate. This introduces the persistence module. It encodes the needed information and its properties indicate precisely where computations has to focus on. The success of persistent homology in applications demands for a multidimensional counterpart. However, the multidimensional case presents theoretical differencies. Here, the persistence module becomes multigraded over a polynomial ring with several indeterminates. The algebraic point of view offers a way to understand the different nature between single and multidimensional theories.
13 maggio 2016 - Aula 706 - Seminario di Italia-Canada per Insegnanti di Scuola Secondaria di I grado (Morselli)
12 maggio 2016 - Aula 706 - Seminario di Didattica (Morselli)
11 maggio 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - G. Caviglia (Purdue University)

"Decidability of Bounds for Projective Dimension and Castelnuovo-Mumford Regularity"

Abstract: A question of Stillman asks: Is there a bound for the projective dimension of every homogeneous ideal generated in a polynomial ring, which depends solely on the knowledge of the degrees of the generators, and not on the number of variables? In joint work with A. Banerjee, we show that for every fixed degree sequence, the correctness of a conjectural bound can be proved by an implementable algorithm.
6 maggio 2016 - Aula 715 - Seminario di Fisica Matematica (Drago)
4 maggio 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Matteo Penegini (University of Genoa)

"Irrational pencils on surfaces with $p_g=q=2$ II"

Abstract: In this talk I will present the proof of the main theorem of part I, which is a joint work with Francesco Polizzi. The proof relies on the Fujita decomposition of the Hodge bundle. Moreover, I will present some examples and applications.
27 aprile 2016 - Aula 704 - Seminario di Seminario dottorandi (Sommariva)
20 aprile 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 15:00 - C. Pedrini

""

Abstract: Franchetta's conjecture on line bundles over the universal curve on the moduli space of curves of genus g, which has been proved by Arbarello and Cornalba , may be stated as follows.
Conjecture 1.1. Let C be the universal curve over the function eld of the moduli space Mg of curves of genus g. Then any line bundle on C is the integral multiple of the canonical bundle,i.e.
(1.2) Pic(C=Mg) ' Z!C=Mg
O'Grady has asked the following question, which is similar to Franchetta
conjecture, for the universal family of K3 surfaces. Let g  3 and let Kg be the moduli space of complex K3 surfaces with a polarization of degree (2g &#1048576; 2). By restricting to the open dense subset Sg = K0
g
parametrising polarized K3 surfaces with trivial automorphism group,
we may assume that the family f : Xg ! Sg is smooth.
Question 1.3. (Generalized Franchetta conjecture) Let Z 2 CH2(Xg).
Is it true that ZjXs 2 ZcXs for all closed points s 2 Sg?.
Here CHi denotes the Chow group of codimension i cycles modulo rational equivalence and cXs denotes the distinguished class of degree
one in the Chow group of 0-cycles on Xs, introduced by Beuville and Voisin. cXs is the class of any closed point P 2 Xs lying on rational curve R.
We will show that Franchetta's conjecture is equivalent to A0(X) '
Q, where X is the generic bre of f and A0 denotes the group of 0-cycles tensored with Q.Using this result we show that the conjecture holds true if g = 3; 4; 5, which are the cases when the projective model in Pg of a general polarized K3 surface of genus g is a complete intersection of g &#1048576; 2 hypersurfaces, and also for g = 6.
13 aprile 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - A. Logar (University of Trieste)

"Border bases for lattice ideals"

6 aprile 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 -

"Parametrization of Groaner cells"

Abstract: The Hilbert scheme of points in the affine plane can be decomposed into Groebner cells: these consist of all ideals which have the same initial ideal with respect to a given term order.
Conca and Valla gave a parametrization of theses cells for the lexicographic term order by finding canonical Hilbert Burch matrices for these ideals.
Constantinescu generalized this for the degreelexicographic term order.
I will present an idea for the parametrization for arbitrary term orders on k[x,y] and talk about some questions that arise: like which monomial ideals correspond to maximal- or minimal-dimensional cells.
All of this is work in progress.
31 marzo 2016 - Aula 716 - Seminario di Logica (Rosolini)
31 marzo 2016 - Aula 706 - Seminario di Fisica Matematica (Pinamonti)

ore 14:00-15:00 -

"Is it possible to have work from a lazy guy?"

Abstract: The appearance of net pressures on perfectly impermeable boundaries, due to the confinement of a quantum field in the vacuum state, raises the question whether and how the conservation of stress-energy tensor allows thermodynamic considerations on the system. It has been recently pointed out an anomalous violation of the First Law for a wedge-shaped geometry. In this talk I will revise the assumptions of the argument, providing a possible explanation of the anomaly in terms of a bad adiabatic approximation and suggesting an analysis which extends to any other geometry
31 marzo 2016 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 15:00-16:00 -

"Condizioni necessarie e sufficienti per moltiplicatori spettrali su gruppi di passo 2"

Abstract:
30 marzo 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Matteo Penegini (University of Genoa)

"Irrational pencils on surfaces with $p_g=q=2$"

Abstract: In this talk (possibly two talks) I will present a joint work with Francesco Polizzi in which we study irrational pencils on surfaces with $p_g=q=2$, completing and extending some previous results obtained by Zucconi.
17 marzo 2016 - Aula 706 - Seminario di Analisi Armonica (Mauceri)

ore 15:00-16:00 - G.Mauceri

"SPAZI DI HARDY: UNA PANORAMICA DI ALCUNI
RISULTATI, CLASSICI E RECENTI"

Abstract:
16 marzo 2016 - Aula 704 - Seminario di Seminario dottorandi (Sommariva)
9 marzo 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 -

"Some remarks about the Nerve Theorem and Betti numbers of monomial ideals"

Abstract: Given a simplicial complex Delta, one can construct its nerve complex by taking as vertices the facets of Delta and as faces the collections of facets of Delta with nonempty intersection. The well-known Nerve Theorem states that this new complex is homotopy equivalent to Delta. What is maybe a bit less known is that one can actually encode both the information about Delta and its nerve inside a bipartite graph. In this talk we will give an overview of this procedure and show, as an application, a correspondence between monomial ideals that preserves the Betti numbers with multidegree 1.
8 marzo 2016 - Aula 706 - Seminario (Beltrametti)
2 marzo 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Hop Dang Nguyen

"Componentwise linearity of some intersection of ideals"

Abstract:
25 febbraio 2016 - Aula 706 - Seminario di Logica (Rosolini)
22 febbraio 2016 - Aula 706 - Seminario di MIDA (Garbarino)

ore 15:00-17:00 - Matteo Santacesaria (Politecnico di Milano)

"Some inverse boundary value problems in two dimensions: theory and applications"

Abstract:
11 febbraio 2016 - Aula 713 - Seminario di Analisi Armonica (Sasso)

ore 15:00 - Adam Nowak (Institute of Mathematics Polish Academy of Sciences)

"Potential operators associated with various orthogonal expansions"

Abstract: We overview our recent results concerning counterparts of the classical Riesz and Bessel potentials in the settings of Jacobi, Hermite, special Hermite, Laguerre, Dunkl-Laguerre, discrete and continuous Fourier-Bessel, and Dunkl-Fourier-Bessel expansions. The results, obtained in collaboration with K. Stempak and L. Roncal, embrace sharp estimates for the potential kernels and complete descriptions of Lp-Lq mapping properties of the potential operators. The latter may be regarded as sharp analogues of the celebrated Hardy-Littlewood-Sobolev theorem in the above mentioned contexts.
10 febbraio 2016 - Aula 713 - Seminario di MIDA (Sommariva)

ore 15:00-16:00 - Federica Sciacchitano, Department of Applied Mathematics and Computer Science, Technical University of Denmark

"Total variation based parameter-free model for impulse noise removal"

Abstract: In this talk, based on total variation (TV), we propose a method for reconstructing blurred images corrupted by impulse noise. Following the idea of the two-phase method, we utilize a noise detector to identify image pixels contaminated by noise, and then we reconstruct the noisy pixels by solving an equality constraint total variation minimization problem that preserves the exact values of the noise-free pixels. The proposed method improves the computational efficiency and has the advantage of being parameter-free. Numerical results suggest that the method is competitive in terms of its restoration capabilities and speed.
3 febbraio 2016 - Aula 704 - Seminario di Soft Computing (Massone)
3 febbraio 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:00 - Filippo Viviani

Margarida Melo

20 gennaio 2016 - Aula 713 - Seminario di Seminario dottorandi (Bruno)
14 gennaio 2016 - Aula 706 - Seminario di Analisi Armonica (De Vito)

ore 15:00 -

"Integrable wavelet transforms with abelian dilation groups"

Abstract: In this talk, we consider semidirect products $G = mathbb{R}^d
times H$,
where $H$ is a suitably chosen matrix group. We assume that $H$ is closed, connected, abelian, and admissible, i.e., it gives rise to a reducible, square-integrable natural representation
acting on $L^2(mathbb{R}^d)$ that has a wavelet inversion formula. We would like to understand whether this representation is also {em integrable}, i.e., if there are wavelets for which the associated
reproducing kernels is in fact integrable.

It is known that the answer to this question is related to topological properties of the unitary dual
$widehat{G}$ of $G$; i.e. a necessary condition is that there exist nonempty open compact subsets of $widehat{G}$. The main general theorem states that, under the additional assumption that all elements of the Lie algebra of $H$ have real spectrum, the (fairly intractable) unitary dual in the necessary condition can essentially be replaced by the orbit space $mathbb{R}^d/H^T$ under the transposed action of $H$ on $mathbb{R}^d$, endowed with the quotient topology. We present several three-dimensional examples that illustrate the complexities that arise.

(Joint with Bradley Currey and Keith Taylor).
13 gennaio 2016 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - J. Rafael Sendra (Universidad de Alcala)

"Simplification of Rational Parametrizations"

Abstract: There exist algorithms to compute rational parametrizations of rational curves and surfaces. These rational parametrizations are not unique, and hence the question of determining a simpler, or even the simplest, parametrization of a given curve or surface arises. In this talk we will describe the problem, we will discuss di_erent criteria for simplicity (injectivity, surjectivity, field of parametrization, height), and we will describe some of the existing approaches.
12 gennaio 2016 - Aula 714 - Seminario di Fisica Matematica (Pinamonti)

ore 16:15 - V. Lanza

"A conjecture of Bruzzo about restricting Higgs bundles to curves"

Abstract: The following result has been proved by Nakayama in 1999: let X be a nonsingular complex projective variety, E a vector bundle on X. If for any morphism f: C->X the pullback f*E is semistable, then E is semistable and the discriminant of E vanishes.
A similar result for Higgs bundles has been recently conjectured by U.Bruzzo. In this talk we shall illustrate the state of the art in solving this conjecture, by focusing in particular on the case in which X is a K3 surface.
12 gennaio 2016 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 15:30 - A. Perelli

"Funzioni L: indipendenza e ortogonalita'"

11 gennaio 2016 - Aula 714 - Seminario di Soft Computing (Massone)
17 dicembre 2015 - Aula 706 - Seminario di MIDA (Sorrentino)

ore 14:00-15:00 - Dr. S. Villa, Laboratory for Computational and Statistical Learning, MIT and IIT

"Forward-backward splitting algorithms with errors"

Abstract: Forward-backward splitting algorithms are among the most popular optimization methods to solve a wide class of signal processing and machine learning problems, often abstracted into a convex composite optimization problem, where the objective function is the sum of a smooth and a nonsmooth component. In this talk I will present convergence results for this class of algorithms, focusing on the influence of computational errors. I will discuss in particular the case of stochastic errors.
10 dicembre 2015 - Aula 706 - Seminario di MIDA (Sorrentino)

ore 14:00-15:00 - R. Ferrando, Chemistry and Industrial Chemistry Department, Univ. of Genoa, Italy

"Alloys at the nanoscale: fascinating structures and properties"

Abstract: Alloy nanoparticles (often known as nanoalloys) are bi- or multi-component metallic particles in the size range between 1-100 nm. Nanoalloys present a wide variety of structures and properties, that make them suitable for many applications to catalysis, optics, magnetism and biomedicine. The practical use of nanoalloys has a very long history, which dates at least to the Roman age. However the precise characterization of their structures and properties is a recent achievement, mainly of the last two decades. Nanoalloys are now a lively research subject, with several aspects worthy of further investigation. After an overview of their main modern applications, we focus on the computational optimization of nanoalloy structures, showing the occurrence of symmetry-breaking phenomena and of morphological instabilities in a wide class of systems.
25 novembre 2015 - Aula 716 - Seminario di Algebra commutativa ()
19 novembre 2015 - Aula 509 - Seminario di Algebraic Statistics Meetings (Zwiernik)
18 novembre 2015 - Aula 716 - Seminario di Algebra commutativa ()

ore 10:00-11:00 -

12 ottobre 2015 - Aula 716 - Seminario (Perelli)

ore 14:30-15:30 - J. Brudern (Universita' di Gottingen)

"The curvature of the primes"

12 ottobre 2015 - Aula 705 - Seminario di (De Vito)

ore 14:30 - Dr. Andreas Maurer

"A chain rule for Gaussian complexities"

Abstract: A recurrent problem in the analysis of multi-layered learning systems is to bound estimation errors uniformly over a composite function class. The talk presents a method to obtain such bounds based on Gaussian averages and sketches some applications to multi-layered learning
8 ottobre 2015 - Aula 713 - Seminario di Algebraic Statistics Meetings (Zwiernik)

ore 14:00-15:00 - P. Zwiernil

"Graphical Gaussian models and their groups"

7 ottobre 2015 - Aula 714 - Seminario di Fisica Matematica (Bartocci)
18 settembre 2015 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)

ore 14:30-16:00 -

""

15 settembre 2015 - Aula 713 - Seminario di Teoria delle Rappresentazioni (Drago)
7 settembre 2015 - Aula 713 - Seminario di Fisica matematica (Bartocci)
7 luglio 2015 - Aula 713 - Seminario di Analisi Armonica (De Vito)

ore 15:00-16:00 - Ubertino Battisti

"THE DISCRETE ORTHONORMAL STOCKWELL TRANSFORM:THEORY AND APPLICATIONS"

3 luglio 2015 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 14:30 - Alessandro De Stefani (University of Virginia, US)

""

Abstract:
2 luglio 2015 - Aula 716 - Seminario di Fisica matematica (Bartocci)

ore 15:00-17:00 -

"Double ramification cycles and integrable systems"

Abstract: In a series of papers with A. Buryak and B. Dubrovin we have studied the intersection theory of the double ramification cycle in the moduli space of stable Riemann surfaces and the related construction of a family of integrable Hamiltonian systems (and their quantization to quantum field theories), dubbed double ramification (DR) hierarchies. The double ramification cycle is, heuristically, the natural locus in the space of Riemann surfaces with n marked points containing curves whose marked points support a principal divisor. Intersection numbers of this locus with other tautological cycles can be arranged into generating functions which are interpreted as Hamiltonians for a (classical or quantum) (1+1)-dimensional field theory. The complicated relations among the intersection numbers translate into integrability of such system. We computed several examples, recovering famous classical integrable systems (KdV, Toda, Intermediate Long Wave, Gelfand-Dickey, etc.) and their previously unknown quantization. We also proved in several cases a conjecture by A. Buryak that the classical limit of the DR hierarchies is equivalent up to a change of coordinates to the classical construction of Dubrovin and Zhang involved in Witten's conjecture.
29 giugno 2015 - Aula 713 - Seminario di Analisi Armonica (De Mari)

ore 14:00 - Alessandro Ottazzi della University of New South Wales (Sydney)

"Il teorema di Sard per la mappa punto finale su alcuni gruppi stratificati"

Abstract:
23 giugno 2015 - Aula 713 - Seminario di Analisi armonica e Probabilita` (Mauceri)

ore 15:00 - G. Mauceri

"Il semigruppo di Mehler su gruppi stratificati"

19 giugno 2015 - Aula 427 - Seminario di Didattica della Matematica (Dapueto)
16 giugno 2015 - Aula 704 - Seminario di Analisi armonica e Probabilita` (Mauceri)
9 giugno 2015 - Aula 713 - Seminario di Analisi armonica e Probabilita` (G. Mauceri)

ore 15:00-17:00 - M. Cowling (University of New South Wales)

"La costante migliore per le disuguaglianze di Hausdorff--Young e Young"

19 maggio 2015 - - Seminario di Analisi armonica e Probabilita` (Mauceri)

ore 15:00-17:00 - G. Mauceri

"Prorieta` di positivita` e contrattivita` di semigruppi associati a forme sesquilineari"

13 maggio 2015 - Aula 713 - Seminario di Fisica Matematica (Pinamonti)

ore 16:30 -

"Covariant phase space, constraints, gauge and the Peierls formula"

Abstract: It is well known that a Poisson bracket may be constructed for a field theory directly from its Lagrangian using the Peierls formula. However the Peierls formula requires the existence of some retarded and advance Green functions, which is not automatic. It is also well known that the canonical symplectic form may also be be constructed directly from the Lagrangian using the covariant phase space method. An elegant argument showing that these two formulas are mutually inverse in the case of scalar field theory with normally hyperbolic equations of motion was given by Forger & Romero [arXiv:math-ph/0408008]. I generalize their argument to arbitrary field theories, which may have constraints and be gauge invariant, provided certain sufficient conditions hold. These conditions include symmetric hyperbolizability of the equations of motion and the vanishing of certain cohomologies of elliptic complexes that extend the constraints and the gauge generators. Based on [arXiv:1402.1282].
12 maggio 2015 - Aula 713 - Seminario di Analisi armonica e Probabilita` (Mauceri)
12 maggio 2015 - Aula 705 - Seminario di Prof. Blanchard (Rosasco)
5 maggio 2015 - Aula 713 - Seminario di Analisi armonica e Probabilita` (Mauceri)

ore 15:00-16:00 - T. Bruno

"Operatori di Schrodinger con spettro discreto"

Abstract:

ore 16:00-17:00 - M. Calzi

"Stime asintotiche del nucleo del calore sul gruppo di Heisenberg III"

Abstract: In questo seminario concludero` le stime asintotiche del nucleo del calore nella regione vicino al centro.
Il risultato estende al caso 2n+1-dimensionale la stima di Hueber e Muller per n=1. Discutero` anche brevemente
il comportamento all'infinito del potenziale dell'operatore di Schrodinger associato al sublaplaciano pesato.
29 aprile 2015 - Aula 713 - Seminario di Teoria dei Numeri (Carletti)
28 aprile 2015 - Aula 706 - Seminario di Analisi armonica e Probabilita` (Mauceri)
24 aprile 2015 - Aula 716 - Seminario di Fisica matematica (Bartocci)

ore 15:00-17:00 -

"Bethe Ansatz and the spectral theory of affine Lie algebra-valued connections"

Abstract: The ODE/IM correspondence is a conjectural relation between a class of affine Lie algebra-valued connections - leading to systems of linear ODEs - and certain algebraic equations, known as Bethe Ansatz and related to quantum Integrable Models. In the simplest case of the algebra $sl_2$, the related ODE is a Schroedinger equation and the corresponding Bethe Ansatz is (strictly related with) the vacuum eingenvalue of the quantum KdV equation.
In this talk, I will describe the results achieved in the recent paper http://arxiv.org/abs/1501.07421 , where we proved the ODE/IM correspondence in the case of simply-laced simple Lie algebras. The techniques used for the proof include the representation theory of simple Lie algebras and affine Kac-Moody algebras, as well as the asymptotic theory of linear ODEs in the complex plane.
24 aprile 2015 - Aula 715 - Seminario di Statistica Algebrica (Riccomagno)

ore 11:00-13:00 - C. Fassino and L. Torrente (Genova)

"Simple Approximate Varieties for Sets of Perturbed Points"

Abstract: This talk consists of two parts. The first part, presented by Maria-Laura Torrente, concerns symbolic-numeric approaches that, starting from a set points X whose coordinates are known with limited accuracy and up to a tolerance epsilon, compute low-degree monic polynomials whose zero-locus gives a good approximation X* of X. The set X* is a set of points whose difference from the corresponding element of X is less than epsilon. The computed polynomials give a simple geometrical description of the starting points. Both the methods illustrated in this talk are a numerical version of the classical Buchberger-Moeller algorithm, but they allow to reach two different aims. The first algorithm (the NBM algorithm) computes low degree polynomials almost vanishing at X; the second one (the LDP algorithm) computes a low-degree polynomial whose associated variety passes close to each point of X by less than the given tolerance epsilon.

The second part of the talk, presented by Claudia Fassino, is about a new variant of the NBM algorithm based on the QR-decomposition. Such new version of the NBM algorithm is more stable than the previous one based on the LU decomposition; moreover the QR-decomposition automatically gives information about the low-degree polynomials almost vanishing at X. Greater diagonal elements of R correspond very probably to terms which are not leading terms of polynomials in the vanishing ideal of X*. Hence the size distribution on the diagonal of R indicates where to find solutions of the homogeneous interpolation problem. We conclude illustrating some applications.
23 aprile 2015 - Aula 705 - Seminario di Vigni (Vigni)
23 aprile 2015 - Aula 704 - Seminario di MIDA (Piana)

ore 15:00 - Francesco Frassoni, Direttore Centro Cellule Staminali e Terapia Cellulare, Istituto Scientifico Gaslini, Genova

"The stem cells' journeys"

22 aprile 2015 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 15:00 -

"Generalizing persistence diagrams to multidimensional persistent homology"

Abstract: Multidimensional persistence modules do not admit a concise rep-
resentation analogous to that provided by persistence diagrams for
real-valued functions. However, there is no obstruction for
multidimensional persistent Betti numbers to admit one. Therefore, it is
reasonable to look for a generalization of persistence diagrams concerning
those properties that are related only to persistent Betti numbers. In
this talk, I review some results recently obtained with A. Cerri. The
persistence space of a
vector-valued continuous function is introduced to generalize the concept
of persistence diagram in this sense. The main result is its stability under function perturbations: any change in vector-valued functions implies a not greater change in the Hausdorff distance between their persistence spaces
21 aprile 2015 - Aula 713 - Seminario di Analisi armonica e Probabilita` (Mauceri)

ore 15:00 - T. Bruno

"Autoaggiunzione e discretezza dello spettro di operatori di Schrodinger"

ore 16:00 - M. Calzi

"Stime asintotiche del nucleo del calore sul gruppo di Heisenberg II: la stima vicino al centro."

14 aprile 2015 - Aula 713 - Seminario di Algebra e Geometria (Varbaro)

ore 15:00 -

"Questioni di razionalita' di 3-folds e 4-folds via categorie derivate "

Abstract: Lo scopo di questo seminario e' di fare un tour di alcuni problemi di razionalita' (alcuni ancora aperti, altri no) tramite degli strumenti di algebra omologica. In particolare, cerchero' di convincervi di come le decomposizioni semi-ortogonali della categoria derivata dei fasci coerenti sembrino offrire un nuovo strumento efficace per studiare tali questioni. Nella seconda parte del seminario mi concentrero' sul caso dei cubic 4folds mostrando una nuova evidenza di una congettura di Kuznetsov
14 aprile 2015 - Aula 705 - Seminario di Analisi armonica e Probabilita` (Mauceri)

ore 15:00 - T. Bruno

"Sublaplaciani pesati e operatori di Schrodinger"

ore 16:00 - M. Calzi

"Stime asintotiche del nucleo del calore del sub-Laplaciano sul gruppo di Heisenberg"

14 aprile 2015 - Aula 713 - Seminario di Statistica Algebrica (Riccomagno)

ore 14:00-15:00 - V. Pirino

"Topological-statistic tools for network dynamics and connectivity in in vitro cortical cultures"

Abstract: To address the issue of extracting useful information from datasets of large scale networks of neurons, I propose an approach that involves both algebraic-statistical and topological tools. The object of study is the electrophysiological behavior of in vitro cortical assemblies both during spontaneous and stimulus-evoked activity coupled to Micro-Electrode Arrays (MEAs). The goal is to identify core sub-networks of repetitive and synchronous patterns of activity and to characterize them.

The analysis is performed at different resolution levels using a clustering algorithm that reduces the network dimensionality. Results are presented via a two-dimensional graphical representation of the detected sub-networks and characterized by topological invariants such as sequences of Betti numbers. The results show that the extracted sub-populations of neurons have a more heterogeneous firing rate with respect to the entire network. Comparison of spontaneous and stimulus-evoked behavior reveals similarities in the identified clusters of neurons, indicating that in both conditions similar activation patterns drive the global network activity.

In order to validate the proposed method, a parameter sensitivity's analysis is performed and a comparison of the proposed methodology with gold standard methods in neuroengineering like Cross-Correlation function and Transfer Entropy algorithm concludes the presentation.
10 aprile 2015 - Aula 704 - Seminario di Soft Computing (Massone)
9 aprile 2015 - Aula 705 - Seminario di Algebra (Varbaro)

ore 14:00-18:00 - G. Bianco (University of Neuchatel)

"Algebraic Geometry in Cryptography: An efficient representation of trace-zero subgroups over Edwards curves"

Abstract: Edwards curves are plane curves of genus 1 and degree 4 that have been recently introduced in cryptographic applications due to the fact that they have the most efficient point addition algorithm. Trace zero subgroups of curves of genus 1 are suitable groups for cryptographic setting both from the point of view of security and of efficiency. These two main motivations lead us to consider trace zero subgroups for Edwards curves over a finite field, and find an efficient way to represent their elements with the least possible number of coordinates in the field of definition of the curve
31 marzo 2015 - Aula 705 - Seminario di Analisi armonica e Probabilita` (Mauceri)

ore 15:00 - T. Bruno

""

ore 16:00 - M. Calzi

"Il nucleo del calore sul gruppo di Heisenberg"

ore 17:00 - G. Mauceri

"Un corso di emergenza sui semigruppi fortemente continui 2"

30 marzo 2015 - Aula 705 - Seminario di Storia della Matematica (C. Bartocci, G. Fenaroli)

ore 15:00 -

""

Abstract:
25 marzo 2015 - Aula 508 - Seminario di Analisi armonica e Probabilita` (Mauceri)

ore 15:00 - Giancarlo Mauceri

"Un corso di emergenza sulla teoria dei semigruppi
fortemente continui."

ore 16:00 - Mattia Calzi

"Il nucleo del calore per il sublaplaciano sul gruppo di Heisenberg"

17 marzo 2015 - Aula 713 - Seminario di Analisi armonica e Probabilita` (Mauceri)

ore 15:00-17:00 - Mattia Calzi

""

Tommaso Bruno

"L'identita` di Bochner e il Laplaciano di Rumin in geometria subriemanniana"

16 marzo 2015 - Aula 704 - Seminario di Mida (Piana)

ore 15:00 - Matteo Santoro, Camelot srl

"Computational Challenges for Image-guided Therapy and Intra-operative Navigation Systems"

12 marzo 2015 - Aula 705 - Seminario di Mida (Piana)

ore 15:00 - Domenico Guadagno e Sebastiano Spotti, CMC Sud

"Introduction to automatic trading: overfitting and portfolio optimization issues"

11 marzo 2015 - Aula 706 - Seminario di Geometria (Vigni)
5 marzo 2015 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
4 marzo 2015 - Aula 713 - Seminario di Statistica Algebrica (Conca)

ore 14:00 - Piotr W. Zwiernik (Univ. Genova)

"Exponential varieties and hyperbolic polynomials"

Abstract: Exponential varieties arise from exponential families in statistics.
These real algebraic varieties have strong positivity and convexity properties, generalizing those of toric varieties and their moment maps. Another special class, including Gaussian graphical models, are varieties of inverses of symmetric matrices satisfying linear constraints. We develop a general theory of exponential varieties, with focus on those defined by hyperbolic polynomials.

j.w. Mateusz Micha&#322;ek, Bernd Sturmfels, Caroline Uhler
26 febbraio 2015 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
25 febbraio 2015 - Aula 713 - Seminario di Algebra (Conca)

ore 14:00 - Antonio Laface (Universidad de Concepcion, Cile)

"COX RINGS"

24 febbraio 2015 - Aula 705 - Seminario di Analisi Armonica (De Vito)

ore 14:00 -

"Adaptive Wavelet Methods for Elliptic Operator Equations: Theoretical Analysis and Practical Realization"

ore 15:00 - Prof. Hartmut Fuhr, Aachen University

"Resolution of the wavefron set using generalized continuous wavelet transforms"

ore 16:00 -

"Disjoint sparsity for signal separation and applications to hybrid imaging inverse problems"

19 febbraio 2015 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 15:00-16:30 - dott. R. Marcovecchio

"Irrazionalita' e trascendenza di costanti classiche: problemi e tecniche"

16 febbraio 2015 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:00 - Victor Reiner (University of Minnesota)

"Invariants mod Frobenius powers"

Abstract: (joint work with J. Lewis and D. Stanton)

The general linear group over a finite field F_q acts on the polynomial algebra with F_q coefficients. L.E. Dickson famously showed that the invariant polynomials form a polynomial subalgebra. Partly motivated by this, we present two closely related conjectures, describing the Hilbert series for

-- the invariants in the quotient by Frobenius powers of the irrelevant ideal,

and

-- the invariants in the divided power algebra.

We will explain the relation between the conjectures, and evidence for them.
12 febbraio 2015 - Aula 716 - Seminario di Teoria dei Numeri (Carletti)

ore 16:00 - E. Carletti

"Funzioni Z"

4 febbraio 2015 - Aula 706 - Seminario di Geometria (Vigni)

ore 16:00-18:00 - Vigni

21 gennaio 2015 - Aula 713 - Seminario di Algebra e Geometria (Conca)

ore 14:30 - J. Rafael Sendra (Universidad de Alcala)

"Rational Parametrization of Algebraic Curves of (approximate) Genus Zero"

21 gennaio 2015 - Aula 705 - Seminario di (De Vito)

ore 16:00 - Dr. Valerya Naumova (Simula Research Laboratory AS, Fornebu, Norway)

"Innovative Regularization Methods in Image and Data Analysis"

14 gennaio 2015 - Aula 716 - Seminario di Fisica Matematica (Pinamonti)

ore 14:30-16:30 - Dr. Alexander Schenkel (Univ. Edinburgh)

"Supergeometry in locally covariant quantum field theory"

10 dicembre 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:30 - Kangjin Han, Seoul, Republic of Korea

"Projection method in syzygies and geometry"

Abstract: As a general hyperplane section method does, a generic projection method has also provided useful ways to treat many problem in algebraic geometry. In this talk we will consider how these generic projection methods can be used to study on properties of projective algebraic varieties, especially on those which are related to the syzygies of the varieties in their embeddings (e.g. graded Betti number, depth, Castelnuovo-Mumford regularity, shapes of Betti tables, higher order normality, etc).
3 dicembre 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:30 - Kangjin Han, Seoul, Republic of Korea

"Syzygy bound on the cubic strand of a projective variety and 3-linear resolutions"

Abstract: Let X be any projective variety in P^N over an algebraically closed field K. Suppose that X is nondegenerate, i.e. not contained in any hyperplane of P^N. Few years ago, K. Han and S. Kwak developed a technique to compare syzygies under projections, as applications they proved sharp upper bounds on the ranks of higher linear syzygies, and characterized the extremal and next-to-extremal cases.

In this talk, we report generalizations of these results, which are on-going with S. Kwak and J. Ahn. We consider a basic degree bound and sharp bounds for generators and syzygies in this cubic strand. Further, the extremal cases will be discussed in the end.
27 novembre 2014 - Aula 715 - Seminario di Algebra (Varbaro)

ore 17:00 -

"Local h-vectors and gamma-vectors: a survey"

Abstract: When dealing with simplicial complexes, a big chunk of information is encoded into the so-called f-vector, which takes into account the number of faces of the complex and their dimension. The h-vector contains the same amount of information as the f-vector but often has nicer algebraic properties.
Kalai and Stanley asked the following question: is it true that, when considering a subdivision of a Cohen-Macaulay simplicial complex, the h-vector of the subdivision is componentwise greater than or equal to the h-vector of the original complex? The answer turns out to be yes, provided the subdivision has nice enough features. In order to get this result, Stanley introduced in 1992 local h-vectors, which proved to have many pleasant properties.
In this talk - based mainly on Stanley's original article and on a recent survey by Athanasiadis - we will review these properties and introduce some other interesting combinatorial quantities, such as the so-called gamma-vector.
Examples and open problems will be discussed.
27 novembre 2014 - Aula 705 - Seminario di Teoria dei Numeri (Perelli)

ore 15:00-16:30 - prof. J. Kaczorowski (Acc. Scienze Polacca)

"General Euler totient functions"

27 novembre 2014 - Aula 704 - Seminario di MIDA Seminar (Piana)

ore 16:00-17:00 -

"Application of connectivity metrics in the study of pathological and physiological brain states"

24 novembre 2014 - Aula 705 - Seminario di MIDA Seminar (Piana)

ore 16:00 - Luca Calatroni, Department of Applied Mathematics and Theoretical Physics, Cambridge University

"Designing customised and reliable Imaging models by bilevel optimisation"

21 novembre 2014 - Aula 716 - Seminario di MIDA Seminar (Piana)

ore 15:00 -

"Measures of Cerebral Connectivity by Means of Magnetoencephalography"

14 novembre 2014 - Aula 217 - Seminario di Teoria delle Categorie (Rosolini)

ore 14:00 - Antonio Vincenzi

""

Abstract:
13 novembre 2014 - Aula 706 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30-16:00 - prof. J. Kaczorowski (Acc. Scienze Polacca)

"Results and problems on analytic semigroups"

12 novembre 2014 - Aula 705 - Seminario di Teoria delle Categorie (Rosolini)

"Immagini conucleari di logiche sottostrutturali"

Abstract:
23 ottobre 2014 - Aula 704 - Seminario di MIDA Seminar (Piana)

ore 15:00-16:00 - A. Diaspro, Istituto Italiano di Tecnologia (IIT)

"Nanoscopy 2.0"

15 ottobre 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:30 - Maria Laura Torrente

"Perturbation results on polynomial zero-loci"

Abstract:
6 ottobre 2014 - Aula 706 - Seminario (De Vito) Pekka Lathi, Department of Physics, University of Turku

"Measurement Uncertainty Relations in Quantum Mechanics"

Abstract: Measurement uncertainty relations are quantitative bounds on the errors in an approximate joint measurement of two complementary observables like position and momentum. They can be seen as a generalization of the error/disturbance tradeoff first discussed heuristically by Heisenberg. Such relations are closely connected with the more familiar preparation uncertainty relations, which constrain the sharpness of the distributions of the two observables in the same state. The talk is based on the following papers:

PRL 111 (2013)160405 (2013) , PRA 89 (2014) 012129, JMP 55 (2014) 042111
16 settembre 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:00-16:00 - Hai Long Dao (Kansas University)

"Projective dimension and homologies of simplicial complexes via domination parameters"

Abstract: Let I be an ideal in a polynomial ring R. The projective dimension is the shortest length of a projective resolution of I. When I is a squarefree monomial ideal, Hochster's Formula allows us to relate projective dimension of I and the homology of subcomplexes of an associated simplicial complex known as the Stanley-Reisner complex of I.

We start with the case when I is the edge ideal of a graph and show how graph domination parameters, invariants which measure how easy it is to cover a graph with various subgraphs, can be used to bound these invariants. Then we explain how these results generalize for any square free monomial ideals, and therefore any simplicial complex.
15 settembre 2014 - Aula 704 - Seminario di Seminario Prof. Beltrametti (Beltrametti)
15 settembre 2014 - Aula 716 - Seminario di Algebra Approssimata (Abbott)
3 settembre 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:30 - Kazuho Ozeki

"The sectional genera and the second Hilbert coefficients of parameter ideals"

15 luglio 2014 - Aula 704 - Seminario di MIDA (Piana)

ore 15:00-17:00 -

"Plastics in lipid membranes"

25 giugno 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:30 - Anthony Iarrobino, Northeastern University

"When do two nilpotent matrices commute?"

Abstract: The similarity class of an n x n nilpotent matrix B over a field k is given by its Jordan type, the partition P of n that specifies the sizes of the Jordan blocks. The variety N(B) parametrizing nilpotent matrices that commute with B is irreducible, so there is a partition Q= Q(P) that is the generic Jordan type for matrices A in N(B). The partition $ Q(P)$ has parts that differ pairwise by at least two, and Q(P) is stable: Q( Q(P))=Q(P). We discuss what is known about the map P to Q(P). A proof of a recursive conjecture by P.~Oblak (2008), was recently announced by R. Basili after partial results by P.~Oblak, T.~Kosir, L. Khatami, and others.
What is the set of partitions $P$ having a given partition $Q$ as maximum commuting orbit? We prove a Table Conjecture of P.~Oblak and R. Zhao for this set when Q has two parts, and generalize it to a Box Conjecture for all stable Q.
This work is joint with Leila Khatami, Bart van Steirteghem and Rui Zhao. If there is time, we will discuss equations for the table loci, work in progress joint also with M. Boij.
18 giugno 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:00 - Ngo Viet Trung (Institute of Mathematics of Hanoi)

"Cohen-Macaulayness of monomial ideals"

Abstract: The topic of the talk lies in the border of Combinatorics and Commutative Algebra.
The talk would begin with a brief introduction on how one can turn problems in one field to the other field via the Stanley-Reisner ideal of a simplicial complex. The focus is on Cohen-Macaulayness of a monomial ideals, especially on how one can use integer programming to study intersections of prime powers such as tetrahedral curves or symbolic powers of Stanley-Reisner ideals.
17 giugno 2014 - Aula 713 - Seminario di Teoria delle Categorie (Grandis)

ore 16:00 - Prof.ssa Marta Bunge

"Pitts Monads and Lax Descent"

11 giugno 2014 - Aula 713 - Seminario di Algebra Geometria (Varbaro)

ore 14:00 - Vasile Brinzanescu (Istituto di Matematica dell' Accademia Romena, Bucarest)

"Moduli spaces of vector bundles on elliptic fibrations"

Abstract: One presents results on semi-stable vector bundles and their moduli on non-Kaehler elliptic principal bundles over compact complex manifolds.
The main techincal tools used are the twisted Fourier-Mukai transform and a spectral cover construction.

ore 15:00 - Luigi Ferraro (University of Nebraska)

"Non-vanishing of Exts"

6 giugno 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30-16:00 - Francesco CELLAROSI (Univ. Illinois at Urbana)

"Ergodic properties of k-free integers"

Abstract: I will present two recent papers motivated by Sarnak's conjecture on the Moebius function. We prove that the sequence (mu^2(n))_n is a typical realization of an ergodic translation on a compact abelian group, strengthening a result by Sarnak. In particular it is a typical realization of a zero entropy random process with no mixing properties. The generalization to arbitrary number fields will also be discussed. Joint works with Ya.G. Sinai and I. Vinogradov.
5 giugno 2014 - Aula 714 - Seminario di Ottimizzazione - Teoria dei Giochi (Pusillo)

ore 14:00-16:00 -

"Unifying efficiency and weak efficiency in vector optimization"

Abstract: In this talk we present some results concerning:
(1) linear scalarizations of proper or weak efficiency;
(2) an algorithm to compute the whole weakly efficient solution set for quasiconvex multiobjective optimization problems on the real-line without derivatives;
(3) a general nonlinear scalarization procedures for a unifying model in vector optimization, and
(4) the equality between the weakly efficient and efficient solution sets with respect to ordering cones having possibly empty interior.
5 giugno 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30-16:00 - dott. Francesco CELLAROSI (Univ. Illinois at Urbana)

"Random k-free integers"

Abstract: I will describe a family of probabilistic models of k-free integers and their statistical properties. These models are inspired by statistical mechanics and are motivated by the recent conjecture by Sarnak on the randomness of the Moebius function. Joint work with Ya.G. Sinai.
3 giugno 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:00 - Michele Torielli (Hokkaido University)

"Resonant bands, Aomoto complex and real 4-nets"

Abstract: In this talk I will recall the notion of a k-net for a line arrangement, describe the connection between this notion, the cohomology of Aomoto complex and the resonant band algorithm. Finally, I will prove that real arrangements that support a 4-net structure do not exist. This is a joint work with M. Yoshinaga.

ore 15:00 - Dumitru Stamate (Institute of Mathematics & University of Bucharest, Romania)

"On the defining equations of the tangent cone of a numerical semigroup ring"

Abstract: Let K be any field. If H is a numerical semigroup, we define its width as the difference between the largest and the smallest of the minimal generators.
If such H is minimally generated by at least 3 elements, the defining ideal I* of the tangent cone grK[H] may have arbitrarily many equations.
We prove that however, if we bound the width of H, then the number of minimal generators of I* is bounded, as well.
We suggest a bound in terms of the width and we present evidence to support this conjectured value.

This is joint work with Juergen Herzog, see arXiv:1308.4644 [math.AC].
22 maggio 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30-16:00 - J.Kaczorowski (Acc. Scienze Polonia)

"Distribution of values of L-functions, IV"

20 maggio 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30-16:00 - J.Kaczorowski (Acc. Scienze Polonia)

"Distribution of values of L-functions, III "

14 maggio 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:00 -

"Commutative Algebra and Hyperplane Arrangements "

Abstract: Several algebraic objects are related to hyperplane arrangements.
For example Orlik-Solomon algebras and Orlik-Terao algebras were studied intensely in the last years. We present recent results related to these algebras and discuss some consequences for hyperplane arrangements.

ore 15:00 - Sudhir Ghorpade (Indian Institute of Technology Bombay)

"Multiplicity and Hilbert series of jet schemes of determinantal varieties"

Abstract: This talk, based on a joint work with Boyan Jonov and Bharath Sethuraman, is basically about two miracles, a little miracle and a not-so-little miracle. These concern the multiplicity and the Hilbert series of the so called principal component of jet schemes of the affine algebraic variety given by the vanishing of 2 x 2 minors of a generic m x n matrix. I will explain what these objects are, discuss related background and results, and attempt to give an idea of the two miracles.
7 maggio 2014 - Aula 713 - Seminario di Algebra Geometria (Varbaro)

ore 14:30 - Victor Lozovanu (Bicocca)

"Newton-Okounkov bodies and positivity of line bundles"

29 aprile 2014 - Aula 705 - Seminario (De Vito)

ore 14:30 - Prof. Dr. Philipp Grohs, Department of Mathematics , ETH Zurich

"Optimal A Priori Discretization Error Bounds for Geodesic Finite Elements"

Abstract: In a number of applications one is led to solve a variational problem where the sought solution is constrained to take its values in a Riemannian manifold. Some examples include harmonic maps into manifolds, variational interpolation in manifolds, chromaticity image denoising or Cosserat material modeling.
Recently, geodesic finite elements have been introduced for the numerical discretization of such problems. They have an elegant covariant formulation and satisfy various desirable equivariance properties.
We prove optimal bounds for the discretization error of geodesic finite elements for manifold-valued partial differential equations in variational form which satisfy a coercivity property. For this we generalize both the well-known Cea lemma and the Bramble-Hilbert lemma to manifold-valued functions. Both of these results are interesting in their own right.
Our theory, which gives a complete extension of well-established linear results, is purely intrinsic and does not rely on embeddings of the codomain into Euclidean space. Special cases are optimal a priori error estimates for the numerical computation of smooth harmonic maps into manifolds using geodesic finite elements, yielding the first high order scheme for this problem.
This is joint work with Hanne Hardering (FU Berlin) and Oliver Sander (RWTH Aachen).
28 aprile 2014 - Aula 704 - Seminario di MIDA (Massone)

ore 16:00-17:00 - Andrew Sommese

"Numerical algebraic geometry over number fields"

Abstract: In this talk we give some background on numerical algebraic geometry and we present some recent work with Tim McCoy and Chris Peterson on how to use numerical analysis, homotopy methods , and continued fractions to decompose an algebraic set defined over a number field into irreducible components over the same number field.
16 aprile 2014 - Aula 705 - Seminario di Algebra (Varbaro)

ore 14:00 - L. Robbiano

"Algebra Lineare e Commutativa"

Abstract:

ore 15:00 - A. Oneto (Stockholm University)

"Power ideals and fat points"

Abstract:
16 aprile 2014 - Aula 704 - Seminario di (Sasso)

ore 14:00-16:00 - D. Bruno

"Modelli statistici applicati alla robotica"

Abstract: Una delle sfide della robotica moderna e' quella di creare robot in grado di interagire con il mondo circostante in maniera intuitiva, in modo da essere facilmente programmabili anche da utenti non esperti. In questo contesto, il paradigma della programmazione pva bene er dimostrazioni permette di trasferire abilita' motorie ad una piattaforma robotica sviluppando modelli compatti a partire da dimostrazioni del compito da svolgere date dall'utente. Tali modelli verranno poi utilizzati per generalizzare il compito a nuove situazioni.

I modelli statistici si sono rivelati un valido strumento per costruire modelli compatti e possono essere utilizzati efficacemente per trasferire abilita' senso-motorie complesse a diverse piattaforme robotiche.

In questo seminario l'attenzione verra' concentrata sull' utilizzo delle Misture di Gaussiane come strumento per costruire modelli e per recuperare rapidamente ed efficientemente da questi le informazioni necessarie per l'esecuzione di attivita' senso-motorie su piattaforme robotiche.
10 aprile 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30-16:00 - J. Bruedern (Univ. Goettingen)

"Linear algebra in cubes"

Abstract: We describe joint work with Trevor Wooley concerning the validity of the Hasse principle for intersections of diagonal cubic hypersurfaces
9 aprile 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:30 -

"Combinatorial duality of Hilbert schemes of points in the plane"

Abstract: The punctual Hilbert scheme is the scheme parametrizing ideals in two variables supported at the origin, or in other words, fat points. A natural decomposition of this scheme is achieved by considering, for each monomial ideal, the subscheme parametrizing ideals having the given monomial ideal as their lexicographic Gr"obner deformation. I will show that these subschemes make for a stratification of the punctual Hilbert scheme. So the closure of each stratum is a disjoint union of strata. This topological fact corresponds to the combinatorial datum of a partial ordering on the set of all monomial ideals. When replacing the punctual Hilbert scheme by the scheme parametrizing all different points in the plane, one obtains a different partial ordering of monomial ideals. I will show that the two partial orderings are dual to each other.
8 aprile 2014 - Aula 322 - Seminario (Pinamonti)

ore 11:00 -

"On preferred states, and the necessity of the Hadamard condition"

7 aprile 2014 - Aula 713 - Seminario di Algebra (Conca)
20 marzo 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30-15:30 - J.Kaczorowski (Acc. Scienze Polonia)

"Distribution of values of L-functions, II"

20 marzo 2014 - Aula 716 - Seminario di Geometria (Gentili)

ore 17:30-18:30 - Carmelo Di Natale (University of Cambridge)

"A period map for global derived stacks"

Abstract: In the Sixties Griffiths constructed a holomorphic map, known as the local period map, which relates the classification of smooth projective varieties to the associated Hodge structures. Fiorenza and Manetti have recently described it in terms of Schlessinger's deformation functors and, together with Martinengo, have started to look at it in the context of Derived Deformation Theory. In this talk we propose a rigorous way to lift such an extended version of Griffiths period map to a morphism of derived deformation functors and use this to construct a period morphism for global derived stacks.
19 marzo 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:30 - Daniele Faenzi (Laboratoire de Mathematiques et de leurs applications - Pau)

"Ideale jacobiano e campi tangenti logaritmici"

Abstract:
18 marzo 2014 - Aula 704 - Seminario di MIDA (PIANA)
18 marzo 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:30 - J.Kaczorowski (Acc. Scienze Polonia)

"Distribution of values of L-functions, I "

17 marzo 2014 - Aula 713 - Seminario di seminario interno ()
12 marzo 2014 - Aula 713 - Seminario di Algebra (Varbaro)

"S. A. Seyed Fakhari (School of Mathematics of Tehran (IPM))"

7 marzo 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 13:45 -

"Local constructions of manifolds"

Abstract:
28 febbraio 2014 - Aula 715 - Seminario di seminario interno ()
20 febbraio 2014 - Aula 713 - Seminario (Torrente Maria Laura)
3 febbraio 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
27 gennaio 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
23 gennaio 2014 - Aula 715 - Seminario di Algebra (Varbaro)
23 gennaio 2014 - Aula 713 - Seminario di Algebra (Varbaro)

ore 12:00-13:00 - Ines Henriques (University of Sheffield)

"F-thresholds and Test ideals for determinantal ideals of maximal minors"

Abstract: Test ideals first appeared in the theory of tight closure, and reflect the singularities of a ring of positive characteristic. Motivated by their close connection to multiplier ideals in characteristic zero, N. Hara and K. Yoshida defined generalized test ideals as their characteristic p analogue. Whereas multiplier ideals are defined geometrically, using log resolutions, or even analytically, using integration, test ideals are defined algebraically using the Frobenius morphism. The generalized test ideals of an ideal I form a non-increasing, right continuous family, {&#964;(c . I)}, parametrized by a positive real parameter c. The points of discontinuity in this parametrization, are called F-thresholds of I and form a discrete subset of the rational numbers (work of Blickle-Musta&#355;&#259;-Smith, Hara, Takagi-Takahashi, Schwede-Takagi, Katzman-Lyubeznik-Zhang). We consider ideals generated by maximal minors of a matrix of indeterminates, in its polynomial ring over a field of positive characteristic. Using an algebraic approach, we give a complete description of their F-thresholds and generalized test ideals.
21 gennaio 2014 - Aula 713 - Seminario di Geometria (Bartocci)

ore 14:15-16:00 - A. Tacchella

"Una famiglia di quiver legata al sistema di Gibbons-Hermsen"

Abstract:
20 gennaio 2014 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:00-16:00 - A. Perelli

"Pair correlation degli zeri della funzione zeta e random matrix theory (Parte Seconda)"

Abstract: Agli inizi degli anni '70 il matematico H.L.Montgomery fece una congettura sulla distribuzione degli zeri della funzione zeta di Riemann, in cui il fisico F.Dayson riconobbe la legge di distribuzione degli autovalori di certe matrici casuali. Circa 10 anni dopo, A.Odlyzko ottenne una spettacolare conferma numerica della congettura di Montgomery, e negli anni '90 P.Sarnak, B.Conrey e J.Keating iniziarono un intenso programma di ricerche sulle analogie tra funzioni L e random matrix theory, tuttora molto attivo.

Il seminario si propone di dare un'idea di queste interessanti ricerche, illustrando a grandi linee alcuni risultati sul versante delle funzioni L e su quello della random matrix theory.
15 gennaio 2014 - Aula 713 - Seminario (Perelli)

ore 14:30 - A. Perelli

"Pair correlation degli zeri della funzione zeta e random matrix theory"

Abstract: Agli inizi degli anni '70 il matematico H.L.Montgomery fece una congettura sulla distribuzione degli zeri della funzione zeta di Riemann, in cui il fisico F.Dayson riconobbe la legge di distribuzione degli autovalori di certe matrici casuali. Circa 10 anni dopo, A.Odlyzko ottenne una spettacolare conferma numerica della congettura di Montgomery, e negli anni '90 P.Sarnak, B.Conrey e J.Keating iniziarono un intenso programma di ricerche sulle analogie tra funzioni L e random matrix theory, tuttora molto attivo.
17 dicembre 2013 - Aula 713 - Seminario di Algebra-Geometia (Conca)

ore 14:00 - Paolo Mantero (University of California, Riverside)

"The projective dimension of codimension two algebras presented by quadrics"

Abstract: Motivated by a celebreatd question of Stillman, we find a sharp upper bound for the projective dimension of ideals of height 2 generated by quadratic polynomials. In a polynomial ring with arbitrary large number of variables, we prove that ideals generated by n quadrics de fine cyclic modules with projective dimension at most 2n-2.
We re fine this bound according to the multiplicity of the ideal and ask whether tight upper bounds for the projective dimension of ideals generated by quadrics can be expressed only in terms of their height and number of minimal generators.
The talk is based on a joint work with C. Huneke, J. McCullough and A. Seceleanu.
12 dicembre 2013 - Aula 427 - Seminario di Seminario Beltrametti Aramini (Beltrametti)
10 dicembre 2013 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:00 - A. Perelli

"Introduzione alla classe di Selberg delle funzioni L"

6 dicembre 2013 - Aula 215 - Seminario di Teoria e Applicazioni delle Categorie (Pagnan)

ore 10:00 - M. Grandis

"Gruppoidi fondamentali come pushout generalizzati di gruppoidi codiscreti (con Ettore Carletti)"

Abstract: Every differentiable manifold X has a 'good cover', where all open sets and their finite intersections are contractible. Using a generalised van Kampen theorem for open covers we deduce that the fundamental groupoid of X is a 'generalised pushout' of codiscrete groupoids and inclusions.
This fact motivates a brief study of generalised pushouts. In particular, we show that every groupoid is, up to equivalence, a generalised pushout of codiscrete subgroupoids, and that (in any category) generalised pushouts amount to connected colimits, and - in the finite case - to ordinary pushouts and coequalisers.
6 dicembre 2013 - Aula 713 - Seminario di Geometria (Bartocci)

ore 14:00 - A. Gentili (Univ. Genova)

"DEFORMATIONS OF A-INFINITY-CATEGORIES"

6 dicembre 2013 - Aula 509 - Seminario di Geometria (Bartocci)

ore 10:00 - V. Lanza (Univ. Genova)

"DEFORMATION THEORY - AN INTRODUCTION (Part 2)"

ore 11:30 - C. Di Natale (Univ. Cambridge)

"DGLA IN DEFORMATION THEORY"

Abstract: The goal of the talk is to show that differential graded Lie algebras naturally arise when dealing with deformation problems. We will introduce the notion of deformation functor and see that this provides the right framework to deal with many deformation problems which arise in Algebra and Algebraic Geometry. Moreover in most examples deformation functors actually come with an attached differential graded Lie algebra: we will analyze this correspondence as deeply as we can.
5 dicembre 2013 - Aula 713 - Seminario di Geometria (Bartocci)

ore 17:30 - V. Lanza (Univ. Genova)

"DEFORMATION THEORY - AN INTRODUCTION (Part 1)"

4 dicembre 2013 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:00 -

"On the Hilbert depth of graded modules over the polynomial ring"

Abstract: In this talk we will introduce and investigate the concept of Hilbert depth of a finitely generated standard Z-graded module over the polynomial ring; we will also show how different the situation in the non-standard Z-graded case is. This is a joint project with J. Uliczka
26 novembre 2013 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:00 - Dott. F. Monopoli (Univ. Milano)

"Combinatorica Additiva"

21 novembre 2013 - Aula 713 - Seminario di Algebra-Geometia (Conca)

ore 14:00 - Nguyen Dang Hop (DIma)

"Finite up to symmetry (I)"

ore 15:00 -

"Finite up to symmetry (II)"

20 novembre 2013 - Aula 713 - Seminario di Algebra-Geometia (Conca)

ore 14:30-15:30 - Winfried Bruns (Osnabrueck)

"On the computation of generalized Ehrhart series"

Abstract: We describe an algorithm for the computation of generalized (or weighted) Ehrhart series based on Stanley decompositions as implemented in the offspring NmzIntegrate of Normaliz. The algorithmic approach includes elementary proofs of the basic
results. We illustrate the computations by examples from combinatorial voting theory. The implementation of NmzIntegrate is based on CoCoALib.
19 novembre 2013 - Aula 705 - Seminario di Teoria dei Numeri (Perelli)

ore 15:30 - P.Corvaja (Udine)

"Su una estensione del problema di Manin-Mumford per certi gruppi algrbrici"

ore 16:30 - J.Kaczorowski (Poznan')

"Twists and resonance of L-functions"

13 novembre 2013 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 14:00-16:00 - F. Monopoli (Univ. Milano)

"Il teorema di Freiman per gruppi abeliani"

4 novembre 2013 - Aula 706 - Seminario di MIDA (Piana)

ore 14:00-16:00 - Maureen Clerc, Athena Project Team, INRIA - Sophia Antipolis

"Theory meets software in electromagnetic brain imaging"

Abstract: Electromagnetic brain imaging deals with the interpretation of the electromagnetic fields of the brain, measured as multi-sensor signals through electro- and magneto-encephalography (EEG and MEG). Dealing with the geometry and conductivity of the head tissues is important in order to deconvolve the mixing process between the brain sources and the signals. This talk will cover forward and inverse problems of electromagnetic brain imaging. On the forward problem, I will present several contributions stemming from the Symmetric Boundary Element Method, from their theory to their software implementation within the Inria software OpenMEEG.
Inverse problems of source localization are subjects of intense research, with many competing approaches. I will explain different strategies for distributed source regularization, as well as isolated dipole localization. Application fields beyond electromagnetic brain imaging, such as Functional Electrical Stimulation, are also concerned with modeling issues of this kind, and I will briefly mention them.
25 ottobre 2013 - Aula 713 - Seminario di Algebra (Varbaro)

ore 14:00 - June Huh (University of Michigan, Ann Arbor)

"Rota's conjecture and algebraic cycles of the permutohedral toric variety"

Abstract: Rota's conjecture predicts that the coefficients of the characteristic polynomial of a matroid form a log-concave sequence. I will outline a proof for realizable matroids using the Bergman fan. The same approach to the conjecture in the general case (for possibly non-realizable matroids) leads to several intriguing questions on higher codimension algebraic cycles in the toric variety associated to the permutohedron.

ore 15:00 -

"Kazhdan-Lusztig-Stanley functions in Coxeter groups"

Abstract: We give a brief introduction to P-kernels and Kazhdan-Lusztig-Stanley functions (they are both elements of the incedence algebra of a poset P) which appear in Coxeter groups, thought as posets under the Bruhat order. We focus our attention to some subposets of a Coxeter group and we show some of their combinatorial and topological properties
2 ottobre 2013 - Aula 713 - Seminario di Algebra e Statistica (Varbaro)

ore 16:30 - Elina Robeva (UC Berkeley)

"Nonnegative Matrix Rank and the EM Algorithm"

Abstract: We study the maximum likelihood estimation problem for the r-th mixture model of two discrete random variables X and Y with m and n states respectively. We apply the EM algorithm to solve this problem and give algebraic equations for the set of all of its possible outputs. We distinguish which of them are critical for the log-likelihood function on the determinantal variety of m x n matrices of rank at most 3 and which are not (and hence lie on the boundary of the mixture model). We explicitly describe the components of the algebraic boundary of this mixture model for r = 3, m = n = 4. This project is work in progress with Bernd Sturmfels and Kaie Kubjas.
26 settembre 2013 - Aula 704 - Seminario (Beltrametti-Pinamonti)
26 settembre 2013 - Aula 713 - Seminario di Algebra (Conca)

ore 15:00 - Martin Kreuzer (Passau)

""

Abstract: After recalling the basic theory of Groebner bases for two-sided ideals in the non-commutative polynomial ring, we present some applications to important problems in geometric and combinatorial group theory: word problem, conjugacy problem, finiteness problem, Tits alternative, and growth rate. In particular, we give an explicit procedure for computing the Hilbert series in many cases. As an example, we show many explicit results for Hecke groups.
25 settembre 2013 - Aula 508 - Seminario di Mathematics of 21st Century: A Personal View (Rossi)

ore 14:30-15:30 - Bruno Buchberger

"Mathematics of 21st Century: A Personal View "

Abstract: Mathematics of 19th century and before was rich in content, intuition,
strong ideas, motivation from natural sciences, and had a coherent view
of all fields of mathematics (geometry, algebra, analysis, number
theory,85).

Mathematics of 20th century added three important aspects:
mathematical logic as the mathematical meta-theory of
mathematics; formalism and abstractness and reduction to first
principles ("Bourbakism"); and the notion of computing (both as
an exact mathematical notion and as the foundation of the
revolutionary device "programmable computer"). In fact, the
three aspects have a lot to do with each other and are
fundamentally interrelated. However, in practice, the three
aspects were
(and still are) pursued by three different communities: The deep
insights of logicians on the nature of mathematics are hardly used in
ever-day practice of "working mathematicians"; "pure mathematicians"
are often proud that they do not touch the computer
except for writing e-mails, typing in LaTeX, and using web search; and
computer scientists often think that what they are doing does not need
mathematics or, even, is opposite to mathematics.

In my view, as indicated by trends in late 20th century, in 21st
century mathematics will evolve as - or return to be - a unified
body of mathematical logic, abstract structural mathematics, and
computer mathematics with no boundaries between the three aspects.
"Working mathematicians" will have to master the three aspects
equally well and integrate them in their daily work. More specifically,
working in mathematics will proceed on the "object level" of
developing new mathematical content (abstract knowledge and
computational methods) and, at the same time, on the "meta-level" of
developing automated reasoning methods for supporting research on the
object level. This "massage of the mathematical brain" by jumping
back and forth between the object and the meta-level will guide
mathematics onto a new level of sophistication.

In the talk, we will exemplify the spirit of this new type of
mathematics by a report on the author's Theorema system, which is both
a logic and a software frame for doing mathematics in the way sketched
above. On the object level, Theorema allows to prove and program within
the same logical frame and, on the meta-level, it allows to formulate
reasoning techniques that help proving and programming on the object
level. In particular, we will show how this type of doing mathematics
allows to mimic the invention process behind the speaker's theory of
Groebner bases, which provides a general method for dealing with
multivariate nonlinear polynomial systems.
2 settembre 2013 - Aula 713 - Seminario di Algebra (Conca)

ore 15:00 - Hara Charalambous (Aristotle University of Thessaloniki)

"Markov bases of lattice ideals"

17 luglio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 -

"Hilbert-Kunz function of some Cohen-Macaulay rings"

Abstract: I will present some numerical invariants of characteristic p rings of finite Cohen-Macaulay type or finite F-representation type. These invariants were introduced in the '90s by Smith, Van der Bergh and Seibert and they encode a lot of informations, such as the Hilbert-Kunz multiplicity or the F-signature. At the end I will present some connection with representation theory.
4 luglio 2013 - Aula 715 - Seminario di Seminari MEPVS (Dapueto)
4 luglio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Juan Migliore (Notre Dame)

""

Abstract:
3 luglio 2013 - Aula 713 - Seminario di Teoria dei Numeri

ore 17:00-18:00 - Sandro Bettin (Univ. Montreal)

"Teoria delle matrici random e teoria dei numeri, II"

1 luglio 2013 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 16:00-17:00 - Sandro Bettin (Univ. Montreal)

"Teoria delle matrici random e teoria dei numeri, I"

25 giugno 2013 - Aula 427 - Seminario di Seminari MEPVS (Dapueto)
25 giugno 2013 - Aula 715 - Seminario di Progetto FIRB

ore 10:00-17:00 - Prof.ssa Umanita`

19 giugno 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - A. De Stefani (U.Virginia)

"Tight closure and F-singularities"

18 giugno 2013 - Aula 704 - Seminario di MIDA (Piana)

ore 11:00-13:00 - Giovanni Naldi, Dipartimento di Matematica and ADAMSS Center, Universita' degli studi di Milano

"Mathematical Modelling of Collective Behaviour: a brief tour with some examples"

Abstract: From biology to cognitive sciences, many modern applications of mathematics are concerned with the dynamics of groups of interacting individuals and the complex phenomena which may emerge from such systems. In the past, models of this type were typically formulated as deterministic differential equations which purport to describe the behaviour of the system as a whole, ignoring the microscopic details of the individual components. More recently, several microscopic (and mesoscopic) ormultiscale models were introduced. In this talk I will try to review some examples involving flocking and synchronization phenomena.
This is a work in collaborations with G. Aletti (Universita' di Milano), G. Toscani (Universita' di Pavia), L. Bleggi (Edison Corporate)
18 giugno 2013 - Aula 705 - Seminario di Algebra (Conca)

ore 14:00 - Aron Simis (Pernambuco)

"Symbolic powers for some linearly presented ideals"

ore 15:00 - Bernd Sturmfels (UC Berkeley)

"Maximum likelihood for matrices with rank constraints"

5 giugno 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Neeraj Kumar

"Vandermonde varieties and relations among Schur polynomials"

ore 15:00 - D. Bolognini

"Computational Homology: an algebraic approach"

30 maggio 2013 - Aula 705 - Seminario di MIDA (Piana)

ore 17:00 - A. Sorrentino

"Sequential Monte Carlo Methods for Bayesian Inverse Problems"

30 maggio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - L. Robbiano

"Parametrizations, hyperplane sections, Hough transforms"

23 maggio 2013 - Aula 706 - Seminario di Teoria dei Giochi (Pusillo)

ore 14:00 - Riccardo Cambini (Universita' di Pisa)

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Abstract:
22 maggio 2013 - Aula 509 - Seminario di MIDA (Piana)

ore 17:00 - Ana Alonso Rodriguez, Dip. Mat., Univ, Trento

"Inverse source problems for eddy current equations"

Abstract: We study the inverse source problem for the eddy current approximation of Maxwell equations. We prove that, as for the full system of Maxwell equations, a volume current source cannot be uniquely identied by the knowledge of the tangential components of the electromagnetic elds on the boundary. We characterize the space of non-radiating sources, i.e., those sources in (L2 (\Omega))^3 that generate an electric eld and a magnetic eld both with zero tangential components on the boundary. We also prove that if the source is not distributed but it is the sum of a nite number of dipoles then the inverse source problem has a unique solution. We investigate the applicability of these results for the localization of brain activity from electroencephalography and magnetoencephalography measurements.
This is joint work with Jessika Camano from the Department of Engineering Mathematics of the University of Concepcion (Chile) and Alberto Valli from the Department of Mathematics of the University of Trento (Italy).
22 maggio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Nguyen Dang Hop

"Koszul algebras defined by matrices of linear forms"

ore 15:00 - E. De Negri

"Looking for the best Grobner bases for ideals of minors"

16 maggio 2013 - Aula 705 - Seminario di MIDA (Piana)

ore 14:30 - Thierry Nieus, Neuroscience and brain technologies, Istituto Italiano di Tecnologia, Genova

"Mathematical modeling of a nervous cell and study of its information processing"

Abstract:
16 maggio 2013 - Aula 715 - Seminario di Teoria dei Giochi (Pusillo)

ore 14:00 -

"Mathematical models for diffusion problems"

Abstract: Diffusion processes of new technologies and services have become increasingly complex and multifaceted in recent years, due to a wide range of influences. In fact, the technology adopters are nowadays exposed to word- of- mouth communications, social signals and network externalities. Diffusion modeling aims at describing these influences and capturing their effects in order to forecast the trend of the product adoption. So, a diffusion model represents the spread of an innovation among adopters. The diffusion of renewable energy technologies (RETs) will be studied and, in particular of wind and photovoltaic ones. Suitable models forecast the RET diffusion process in Italy, this model incorporates the time-varying nature of the word-of-mouth influence with a coefficient of imitation changing over time. Also mathematical model with time delay (Delay Differential Equation ) are proposed to describe the process of diffusion of a new technology. The time delay represents the evaluation stage at which the potential consumers decide whether to adopt the new technology or not. A qualitative analysis is carried out in order to assess the stability of the equilibrium for certain parameters.
15 maggio 2013 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 15:00-16:00 - dott. Giuseppe Molteni (Univ. Milano)

"Una nuova versione esplicita del teorema degli ideali primi per le funzioni zeta di Dedekind sotto GHR"

15 maggio 2013 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)

ore 16:00 - G. Rosolini

"Sobrio dentro"

Abstract:
15 maggio 2013 - Aula 508 - Seminario ()
15 maggio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00-15:00 - M.E. Rossi

"Linearity defect of modules"

9 maggio 2013 - Aula 705 - Seminario (Riccomagno)

ore 15:00-17:00 - Prof J. L. Hutton, Department of Statistics, University of Warwick

"Joint modelling of pre-randomisation event counts and multiple postrandomisation survival times with cure rates: application to data for
early epilepsy and single seizures (joint with JK Rogers, AG Marson, DW Chadwick)"

Abstract: We consider the analysis of recurrent event data that examines the differences between two treatments. The outcomes that are considered in the analysis are the pre-randomisation event count and post-randomisation times to first and second events with associated cure fractions. We develop methods that allow pre-randomisation counts and two post-randomisation survival times to be jointly modelled under a Poisson process framework, assuming that outcomes are predicted by (unobserved) event rates. We apply these methods to data that examine the difference between immediate and deferred treatment policies in patients presenting with single seizures or early epilepsy. We find evidence to suggest that post-randomisation seizure rates change at randomisation and following a first seizure after randomisation. We also find that there are cure rates associated with the post-randomisation times to first and second seizures.
The increase in power over standard survival techniques, offered by the joint models that we propose, resulted in more precise estimates of the treatment effect and the ability to detect interactions with covariates.
8 maggio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Michal Lason, (Polish Academy of Sciences, Warsaw)

"A selection of challenging problems concerning matroids"

ore 15:00 - Mateusz Michalek, (Max Planck Institute, Bonn and Polish Academy of Sciences, Warsaw)

"Secants, cumulants and group actions"

30 aprile 2013 - Aula 714 - Seminario di Geometria e fisica (Bartocci)
24 aprile 2013 - Aula 705 - Seminario di Geometria e fisica (Bartocci)
24 aprile 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - M. Varbaro

"D-modules (2)"

17 aprile 2013 - Aula 705 - Seminario di Geometria e fisica (Bartocci)
17 aprile 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - M. Varbaro

"D-modules (1)"

12 aprile 2013 - Aula 218 - Seminario di Teoria delle Categorie (Pagnan)

ore 14:00 - T. Streicher (TU Darmstadt)

"A Classical Realizability Model arising from a Model of Lambda Calculus in Stable Domain Theory"

ore 15:00 - F. Pasquali (Genoa)

"A Co-free Construction for Elementary Doctrine"

ore 16:00 - G. Rosolini (Genoa)

"Sober Inside"

12 aprile 2013 - Aula 218 - Seminario di Teoria delle Categorie (Pagnan)

ore 10:00 - J. van Oosten (Utrecht)

"Realizability with Hyperarithmetical Functions"

ore 11:00 - R. Pagnan (Genoa)

"Syllogistic Coherence in Autonomous Categories"

12 aprile 2013 - Aula 704 - Seminario di MIDA (Piana)
10 aprile 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - A. Conca

"Maximal minors with linear powers"

9 aprile 2013 - Aula 509 - Seminario di Teoria delle Categorie (Pagnan)

ore 14:00-18:00 - Rasmus Ejlers Mogelberg

"Presheaf models for guarded recursion"

Abstract: A guarded recursive definition is one where the recursion variable only occurs in positions guarded by a delay operator. In this talk I will present a new model of guarded recursion and motivate it using two different examples: first as a model for computations with coinductive types such as streams, and second as a model of a metalanguage useful for defining models of programming languages with higher-order store.

The model is a simple presheaf model (over the ordered natural numbers) and I will describe the computational intuition. If I have time I will describe recent work on reducing guarded recursive types to guarded recursive terms using universes and on constructing models of intensional type theory with guarded recursion.

Most of the talk describes joint work with Lars Birkedal, Kristian Stoevring and Jan Schwinghammer published at LICS 2011, but I will also talk about joint work with Lars Birkedal to appear at LICS 2013.
4 aprile 2013 - Aula 706 - Seminario di Post-doc INdAM (Conca)
27 marzo 2013 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)

ore 16:00 - G. Rosolini

"La soluzione di Matiyasevich del decimo problema di Hilbert (seconda parte)"

Abstract: nella seconda parte del seminario affronteremo alcuni dettagli tecnici del risultato ottenuto da Y. Matiyasevich. In particolare, dopo aver richiamato le definizioni iniziali delle categorie coinvolte, presenteremo i dettagli dei seguenti punti:
* il teorema di punto fisso alla base della soluzione
* la codifica della logica mediante equazioni diofantee
* il lemma che (il grafo del)la funzione esponenziale e' diofanteo
* la soluzione del decimo problema
27 marzo 2013 - Aula 704 - Seminario di MIDA (Piana)

"A Regularization Framework for Multitask Learning"

Abstract: A fundamental limitation of standard supervised machine learning methods is the cost incurred by the preparation of the large training samples required for good generalization. A potential remedy is offered by multitask learning: in many cases, while individual sample sizes are rather small, there are samples to represent a large number of learning tasks, which share some constraining or generative property. If this property is sufficiently simple it should allow for better estimation of the individual tasks despite their small individual sample sizes. In this talk we present a regularization framework for multitask learning which builds upon ideas from kernel methods and sparse estimation. We highlight certain forms of the regularizers which encourage shared low dimensional or sparse representations of the data, we address the predictive properties of these methods, and we describe numerical techniques to solve the underlying regularization problem. Finally, we report on som e multitask learning applications arising in the areas of affective computing, computer vision and user modelling.
27 marzo 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Ramakrishna Nanduri

"Castelnuovo-Mumford regularity and Gorensteinness of fiber cone"

20 marzo 2013 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)

ore 16:00 - G. Rosolini

"La soluzione di Matiyasevich del decimo problema di Hilbert"

20 marzo 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Oscar Fernandez

"On the regularity of bipartite edge ideals"

19 marzo 2013 - Aula 704 - Seminario di COCOA (Bigatti)
14 marzo 2013 - Aula 713 - Seminario (Del Prete, Astengo)
13 marzo 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Nguyen Dang Hop

"Koszul algebras and Frobenious endomorphisms"

ore 15:00 - E. De Negri

"Universal Groebner bases for maximal minors (II)"

13 marzo 2013 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)

ore 16:00 - R. Pagnan

"Syllogistic coherence in autonomous categories"

Abstract: An autonomous category is a closed symmetric monoidal category.
In this seminar I will talk about the work in progress concerning a research that I am currently pursuing, about the eventual connections that I think may exist between a specific coherence problem for autonomous categories and a possible solution for it by means of a graphical logical calculus for the Aristotelian syllogistic.
Roughly, in category theory, a coherence theorem is a result establishing that all the diagrams constructed in accordance with the definitory data of a categorical structure commute in all the categories that carry such a structure. So, coherence theorems concern suitable structures in abstract. This is a viewpoint that has been extensively investigated by Mac Lane, Kelly and others.
I will briefly describe the coherence problem for the autonomous structure in abstract, that is for the free autonomous category over a collection of generators, F. Without entering into the details, I will comment on the so-called Kelly-Mac Lane graphs employed for its solution. Relevant considerations on the problem at issue from the viewpoint of Rudimentary Linear Logic will be provided.
I will try to describe what I call the "syllogistic core" of F and its connection with the previously hinted at diagrammatic calculus
11 marzo 2013 - Aula 705 - Seminario (De Vito)

ore 15:00 - L. Rosasco, DIBRIS & Laboratory for Computational and Statistical Learning (IIT--MIT)

"Towards a Statistical Theory of Learning Representation from Data"

Abstract: Machine learning has played a central role in the recent successes of artificial intelligence and provided fundamental tools for analyzing complex, high dimensional data in Science and Engineering. A main bottleneck of current machine learning systems is the large amount of labeled data required, which in turn calls for intense computations and considerable human supervision. Data representation is broadly acknowledged to be key in solving the above problems. The intuition that these algorithms adaptively reduce the degrees of freedom in the data, and lead to improved performances, is confirmed by promising empirical results. However, these intuitions and empirical observations are not grounded in a solid theoretical foundation, a fact that arguably hinders progress in the field.
In this talk I will present an approach to establish a statistical theory of learning representations from data akin to the classic supervised statistical learning theory. The theory we propose borrows ideas from Signal Processing (and Harmonic Analysis), Machine Learning and Statistics, while establishing novel bridges between such diverse field as Optimal Quantization, Optimal Transport Theory and Computational Geometry. Computational solutions for learning representations from data, based on piecewise linear and multiscale models, will be presented and studied.
6 marzo 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - P. Gianni (Pisa)

"Ideals of curves given by points"

Abstract: Let C be an irreducible projective curve of degree d in Pn(K), where K is an algebraically closed field, and let I be the associated homogeneous prime ideal. If I can be generated by polynomials of degree at most m and md + 1 points on C are given, a minimal set of generators for I is constructed in polynomial time (in n and m). The construction is based on properties of border bases. Given a fixed choice of complement for a zero-dimensional ideal, its border basis is uniquely determined in contrast with Grbener bases where the complement is uniquely determined by the given term ordering. Border bases are usually defined for zero-dimensional ideals, but the bounds on the degree of the generators allow to extend the definition to homogeneous ideals of any dimension. The constructions are completely independent of any notion of term ordering. This allows the complement to be chosen to maximize numerical stability. Also some classical bounds on the degrees of the generators for ideals of curves are recalled
5 marzo 2013 - Aula 509 - Seminario di Processi Stocastici ()
27 febbraio 2013 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)
27 febbraio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - M. Varbaro

"J-multiplicity"

25 febbraio 2013 - Sala conferenze DIBRIS - Seminario (De Vito)

ore 15:00 -

"Gram matrix estimation in high dimension"

20 febbraio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - E. De Negri

"Universal Groebner bases for maximal minors"

20 febbraio 2013 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)

ore 16:00 - E. Moggi

"Categories for Collection Types (part 2)"

Abstract: In this second part, we will
- propose category-theoretic models, for fragments of Martin-Lof extensional type theory, suitable for collection types
- show that in them the analogue of P_f (finite powerset monad) can be defined as a decidable quotient of a polynomial functor
- show that the concrete examples (described in part 1) are instances of such models.
14 febbraio 2013 - Aula 704 - Seminario di MIDA (Piana)

ore 17:00 - G. Alberti, Oxford Centre for Nonlinear PDE

"A multi-frequency approach to microwave imaging by ultrasound deformation"

Abstract: Hybrid medical imaging techniques have been developed in recent years in order to obtain high contrast and high resolution images. We present the hybrid inverse problem arising from the combination of microwave measurements with ultrasound deformation. We provide a reconstruction algorithm that is applicable if the solutions of the Helmholtz equations satisfy certain qualitative properties, e.g. the lack of any critical points. The common way to construct such solutions relies on the knowledge of the associated electromagnetic parameters of the PDE, which in fact are unknown. In order to overcome this issue, we propose a new multi-frequency approach which also turns out to be applicable in several other situations.
13 febbraio 2013 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)

ore 16:00 - E. Moggi

"Categories for Collection Types"

Abstract: Collection types have been proposed as a suitable way to capture database query languages in a type-theoretic setting.
In 1998 Manes introduced the notion of collection monad on the category of sets as a suitable semantics for collection types. The canonical example of collection monad is the finite powerset monad.
In order to account for the algorithmic aspects of database languages, the category of sets is unsuitable, and should be replaced with other categories, whose arrows are functions computable by low complexity algorithms.
We propose a class of categories, that are more general than locoses, and
meet the following desiderata:
- in them one can define an analogue of the finite powerset monad and recast the notion of collection monad;
- concrete examples include standard set-theoretic models, and also models based on low complexity numeric functions (like those in level 2 of Grzegorczyk hierarchy, or equivalently computable in linear space);
- in them one can interpret a significant fragment of Martin-Lof extensional type theory.
13 febbraio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Oscar Fernandez

"Laplace equations and the weak lefschetz property"

11 febbraio 2013 - Aula 705 - Seminario di (De Vito) Rosasco

6 febbraio 2013 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)

ore 16:00 - F. Pasquali

"A co-free construction for elementary doctrines"

Abstract: In this talk I present a construction that adds elementary structure to an elementary doctrine in a co-free way. The construction preserves comprehensions and all the first order logical operations which are in the starting doctrine, in the sense that it maps any first order many-sorted theory in a first order many-sorted theory formulated with equality. As a corollary it forces a higher order theory to have extensional entailment
6 febbraio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - Ramakrishna Nanduri

"Free divisors"

30 gennaio 2013 - Aula 713 - Seminario di Post-doc INdAM (Conca)

ore 14:00 - A. Conca

"Bounding degrees of syzygies for Koszul algebras"

28 gennaio 2013 - Aula 704 - Seminario (Fassino)

ore 15:00 - H. M. Moller (Universitat Dortmund, Germany)

"A new algorithm for fitting surfaces with disturbed data"

Abstract: Thirty years ago, the Buchberger-Moeller algorithm solved the problem of fi nding a Groebner basis of the ideal of polynomials vanishing in a given fi nite set of points X.
Unfortunately, this algorithm is not suited for computations with disturbed data. If only approximations X' of the elements of X are known, then only polynomials p can be found with small values at X'. The algorithm presented here computes sucessively for increasing degrees polynomials which minimize || P(X') ||^2. It is based on a numerically stable variant of the QR-decomposition of matrices and developed in cooperation with Claudia Fassino (Univ. Genova).
14 gennaio 2013 - Aula 704 - Seminario di MIDA (Piana)
11 dicembre 2012 - Aula 218 - Seminario di Processi Stocastici ()
11 dicembre 2012 - Aula 714 - Seminario di Analisi Funzionale (Baronti)

ore 15:00 -

"Representation of convex sets in Banach spaces"

28 novembre 2012 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
26 novembre 2012 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 17:00 - Prof. J. Kaczorowski (Acc. Scienze Polacca)

"Twists of L-functions - part III"

22 novembre 2012 - Aula 715 - Seminario di Teoria dei Numeri (Perelli)
19 novembre 2012 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 17:00 - Prof. J. Kaczorowski (Acc. Scienze Polacca)

"Twists of L-functions - part II"

14 novembre 2012 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)

ore 17:00 - Prof. J. Kaczorowski (Acc. Scienze Polacca)

"Twists of L-functions - part I"

7 novembre 2012 - Aula 714 - Seminario di Statistica Matematica (Riccomagno)
5 novembre 2012 - Aula 713 - Seminario di Algebra Geometria (L. Badescu)

ore 16:00 - A. Dimca (Univ. Nizza)

"Syzygies of the Jacobian ideal"

Abstract:
11 ottobre 2012 - Aula 704 - Seminario di MIDA (Piana)

ore 16:00 - D. Vitulano, Ist. Applicazioni del Calcolo cnr - iac, Roma

"Transients and wavelet atoms"

Abstract: A novel model for signal and image multiscale analysis will be presented. In particular, the flow of transients information will be analyzed in the time (space) scale plane independently of the adopted differentiation operator. More precisely, significant extrema points of a suitable time scale decomposition of the analysed signal (image) and the trajectories of these extrema points are provided. This establishes a strong link through subsequent scales, so that it is possible to predict the evolution of a singularity point in the original signal(image) from fine to (any) coarse resolution, rejecting both noise and non significant points. Different applications will be presented that show the potential of this approach, since it is able to simultaneously describe both dominant singularities and fine details.
3 ottobre 2012 - Sala conferenze DIBRIS - Seminario (De Vito)

ore 15:00 - Prof. P.L. Combettes, Lab. Jacques-Louis Lions, Fac. Math.,, Univ. Pierre et Marie Curie - Paris 6,

"Proximal Information Modeling and Processing in Learning Theory and Inverse Problems"

Abstract: A central issue in learning theory and inverse problems is to extract reliably information from large data sets while promoting consistency with a priori knowledge. We discuss modelling and algorithmic tools, based on the notion of a proximity operator, that make it possible to achieve this goal for a broad class of problems. Special emphasis will be placed on the importance of duality, both in problem modelling and solution algorithms. In particular, using the self-duality of the class of proximity operators, connections will be established between notions such as robustness, smoothing and regularization. On the other hand, apparently unrelated algorithms will be brought together in a single framework. Finally, sparsity modelling will be considered from a general proximal viewpoint. Various applications will be discussed.
4 settembre 2012 - Aula 713 - Seminario di ()

ore 11:00 - Prof. R. Olkiewicz, Inst. of Theoretical Physics, Wroclaw

"Strong decoherence in quantum systems with diffusion type interaction"

9 luglio 2012 - Aula 706 - Seminario (Conca)

ore 15:00 - G. Caviglia (Dept. Math,, Purdue University), O. Dmitrieva (Dept. Linguistics, Stanford University)

"Monomial orders: from computational algebra to linguistic typology"

Abstract: A monomial order is a total order, compatible with multiplication, defined on the set of all monomials of a polynomial ring.
In 1920's Macaulay introduced these orderings to caractherize all possible Hilbert functions of graded ideals by comparing them to monomial ideals.
Subsequently Grobner and his student Bruno Buchberger used them to associate to a graded ideal a set of multivariate polynomials with desirable algorithmic properties, called a Grobner basis.
Grobner bases have a wide range of applications, not only in algbera and algebraic geometry but also in many sciences in which polynomial models
are used. A general principle is that many numerical invariants of a set of polynomials can be computed, or at least bounded, by studying certain monomials determined by a Grobner basis.
In this lecture we will first give an overview of this principle in both commutative and computational algebra. We will then use monomial orders to explain the analogies between two distinct, yet similar, theories in phonology: Optimality Theory and Harmonic Grammars.
In particular we will show how to use a mathematical object, called Grobner fan, to build models of linguistic typology.
3 luglio 2012 - Aula 713 - Seminario di Algebra Geometria (Conca)

ore 14:30 - Luke Oeding (University of California, Berkeley)

"Hyperdeterminants of a polynomials"

Abstract: Hyperdeterminants were brought into a modern light by Gel&#697;fand, Kapranov, and Zelevinsky in the 1990's. Inspired by their work, I will answer the question of what happens when you apply a hyperdeterminant to a polynomial (interpreted as a symmetric tensor).
The hyperdeterminant of a polynomial factors into several irreducible factors with multiplicities. I identify these factors along with their degrees and their multiplicities, which both have a nice combinatorial interpretation. The analogous decomposition for the &#956; discriminant of polynomial is also found.
The methods I use to solve this algebraic problem come from geometry of dual varieties, Segre-Veronese varieties, and Chow varieties; as well as representation theory of products of general linear groups.

ore 16:00 - Hop Nguyen (Osnabrueck)

"Algebra retracts of Stanley-Reisner rings"

Abstract: In a series of papers in 2000's, Bruns and Gubeladze proposed a generalization of linear algebra by introducing many ``polytopal linear algebra" results. An example being the computation of the polytopal linear group, that is, the graded automorphism group of a polytopal algebra. This computation resembles in many ways the description of the genaral linear group $GL(n,k)$. One of the remaining problem in this programm is the following conjecture: every graded algebra retract of a polytopal algebra is a again a polytopal algebra. (See the paper "Polytopal linear retractions", Trans. Amer. Math. Soc. 354 (2002), 179-203). In this talk, I will explain the significance of this conjecture and prove an analogue of it for Stanley-Reisner rings. It turns out that there is also a feasible conjecture for monomial quotient rings. (This is a joint work with Neil Epstein.)
27 giugno 2012 - Aula 706 - Seminario (Dapueto)

Pagina web

ore 15:00 - prof. B. Pollack-Johnson

"Using Semester-Long Student Projects for Deeper Learning in Calculus, Operations Research, and other Mathematics Courses"

Abstract: In a subject like calculus, students can learn concepts, theorems, and techniques for operations such as differentiation from lectures, text (hard copy or online), and doing exercises. For many students, when they can connect a topic to real life, especially something in their own lives, they can achieve a better understanding of its importance and a deeper understanding of the concepts. In this presentation, I will show how projects extending over months can be structured to bring about such deeper understanding and to help students learn the entire process of solving real-world problems by collecting their own data, and then using mathematical models, optimization concepts, and technology.
13 giugno 2012 - Aula 713 - Seminario di Algebra Geometria

ore 14:00 - Asia Rauf

"Construction of Cohen-Macaulay binomial edge ideals"

ore 15:15 - Lukas Katthaen

"Holes in affine monoids"

6 giugno 2012 - Aula 705 - Seminario di MIDA (Piana)

ore 17:00 - A. Sommese, Univ. of Notre Dame

"Numerical algebraic geometry and systems of nonlinear differential equations"

Abstract: many important problems in engineering and science lead to systems of partial differential equations, for which the only hope of solution is to compute numerical solutions. often the systems are intrinsically nonlinear with several solutions corresponding to the same set of physical conditions. discretizations of such systems of differential equations often lead to large systems of polynomial equations, some of whose solutions correspond to solutions of the system of differential equations. these naturally arising polynomial systems are much larger systems previously investigated in numerical algebraic geometry.
5 giugno 2012 - Aula 704 - Seminario (Beltrametti)
5 giugno 2012 - Aula 704 - Seminario di Ottimizzazione - TdG (Pusillo)

ore 16:00 - Prof. Bruce Pollack-Johnson, Associate Prof. of Math. and Stat., Villanova Univ.

"Optimizing Project Schedules Using Models that Incorporate Quality as well as Time and Cost"

Abstract: Traditional project scheduling (PERT/CPM, time-cost tradeoffs) assumes implicitly that the quality of tasks and a project overall are held constant, but this is not always possible in the real world. In this presentation, we discuss how quality can be modeled in project scheduling to be able to look at the tradeoffs between time, cost, and quality simultaneously. The models involved include mixed integer programs. We illustrate with real data from case studies of a translation agency and a software development company. This research is joint work with Matthew Liberatore, Ph.D., John Connelly Chair of Management at the Villanova School of Business of Villanova University. Professor Pollack-Johnson is currently working on extending this research in collaboration with Professor Eva Riccomagno
29 maggio 2012 - Aula 704 - Seminario di Ottimizzazione - TdG (Pusillo)

ore 14:00 - prof. F. Facchinei, (Univ. Roma 1 La Sapienza)

"Distributed algorithms for the solution of (generalized) Nash equilibrium problems."

Abstract: The talk is divided into two parts. In the first, introductory part the (generalized) Nash equilibrium problem is presented and an overview of recent results related to their numerical solution is discussed. The second part is devoted to study of (distributed) algorithms for the solution of the "Nash selection problem", extending and unifying several cases considered in the first part. Applications to a resource allocation problem in telecommunications will be presented.
23 maggio 2012 - Aula 706 - Seminario (Boero)

ore 15:30 - prof.ssa E. Aitzkovich

22 maggio 2012 - Aula 704 - Seminario di Ottimizzazione - TdG (Pusillo)

ore 14:00 - prof. G. Pieri

"Stackelberg Problems with Followers in the Grand Coalition of a TU-game"

Abstract: In this talk a case of partial cooperation in game Theroy framework is presented.
The problem is about a bi-level Stackelberg model, where one player is a leader and the others are the followers involved in a TU-game.The continuity with respect to the leader choice, of the Shapley value fuction and the core correspondence of the TU-game is investigated.
18 maggio 2012 - Aula 716 - Seminario (Sasso)

ore 11:00 - A. Toigo (Politecnico di Milano)

"Normal completely positive maps on the space of quantum operations"

Abstract: We define a class of higher-order linear maps that transform quantum operations into quantum operations and satisfy suitable requirements of normality and complete positivity. For this class of maps we prove two dilation theorems that are the analogues of the Stinespring and Radon-Nikodym theorems for quantum operations. A structure theorem for probability measures with values in this class of higher-order maps is also derived.
18 maggio 2012 - Aula 713 - Seminario di MIDA (Piana)

ore 16:00-18:00 - G. Emslie, West Kentucky Univ.

"mathematical models for electron acceleration in solar flares"

16 maggio 2012 - Aula 713 - Seminario di Algebra Geometria (Conca)

ore 14:00 - N. Kumar

"Regular sequences of power sums and complete symmetric polynomials"

Abstract: Let $S=\mathbb{C}[x_1,x_2,\dots,x_n]$ for $n \geq 3$ be a polynomial ring. Denote by
$p_k(n)=x_1^k+x_2^k+\cdots +x_n^k$, the power sum symmetric polynomial and complete symmetric polynomials by
$h_k(n)$, the sum of all monomials of degree $k$ in $S$.
We will recall main results and conjectures given by Conca, Krattenthaler, and Watanabe on regular sequences of power sums and complete symmetric polynomials, and provide evidence of the conjecture by proving in special instances. We will show any
power sums of the form
$p_a,p_{a+1},\dots, p_{a+m-1},p_b$ with $m<n-1$ forms a regular
sequence in $S$. Any two power sum element in $S$ forms a regular sequences. We will see some more results on three power sum elements in four variable, forming a regular sequences
9 maggio 2012 - Aula 713 - Seminario di Algebra Geometria (Conca)

ore 14:00 - Tran Nam Trung

"Stability of depths of powers of edge ideals"

Abstract: Let $I$ be a Stanley-Reisner ideal of a polynomial ring $R$ over
a field. We show that the sequence $\depth R/I^{(n)}$ is stable for all
$n$ sufficiently large. For a simple graph $G$, how large of $n$ such that
$\depth R/ I(G)^n$ stabilizes is given and this bound can always be
achieved for connected graphs with at most one cycle.
3 maggio 2012 - Aula 713 - Seminario di Algebra Geometria

ore 16:00 - Wen-Shin Lee, Univ. of Antwerp

"Searching for Sparsity"

Abstract: Lately, sparsity has emerged as an important concept in signal processing. Smaller and smarter information devices demand ever more sophisticated techniques to acquire and process data. Sparse methods are the key to meet the challenges in many applications.

At the same time, research in sparse models has existed for decades. In computer algebra, sparse interpolations and representations are developed to improve computational performance. Recent achievements in symbolic-numeric sparse interpolation allow both the input and outputs, with some added noise, represented in a finite precision environment.

A connection to the associated structured matrices enables symbolic-numeric sparse interpolation algorithms to be generalized to a wider class of function representations. We plan to discuss related issues in linear algebra and explore certain applications, including indentifying compact representations of biomedical signals.

This is joint work with Annie Cuyt.
2 maggio 2012 - Aula 705 - Seminario di Algebra Geometria (Conca)

ore 14:00-15:00 - Prof. L. Robbiano

"Detecting Hidden Curves Using Algebraic Schemes "

24 aprile 2012 - Aula 713 - Seminario di Algebra Geometria (Conca)

ore 14:00 - MINH NGUYEN CONG

"On the Cohen-Macaulay graphs and girth"

Abstract: In this talk, we investigate the Cohen-Macaulay property of graphs versus girth. In particular, we will classify all Cohen-Macaulay graphs of girth at least five and planar Gorenstein graphs of girth four. This is joint work with Do Trong Hoang and Tran Nam Trung.
18 aprile 2012 - Aula 713 - Seminario di Algebra Geometria (Conca)

ore 14:00 - Dott. M. Varbaro

"COHOMOLOGICAL AND PROJECTIVE DIMENSIONS "

Abstract:
17 aprile 2012 - Aula 713 - Seminario di Ottimizzazione - TdG (Pusillo)

ore 14:00 - prof. B. Codenotti, direttore Ist. Informatica - CNR Pisa

"COMPUTATIONAL GAME THEORY"

Abstract: With the advent of the Internet, certain branches of Computer Science have imported tools from Game Theory. The characterizing feature of the interplay between Computer Science and Game Theory turns out to be the notion of Nash equilibrium, which is the key solution concept for noncooperative games. Its computational properties give rise to new complexity classes, and provide new insights into a wide variety of related mathematical problems. In this lecture, we will discuss some of the most relevant computational questions connected with Nash equilibria. We will also outline some connections with problems arising in other scientific fields.
4 aprile 2012 - Aula 713 - Seminario di Algebra Geometria (Rossi)

ore 14:00 - prof. A. Conca

"Regularity of Koszul homology"

28 marzo 2012 - Aula 713 - Seminario di Algebra Geometria (Conca)

ore 14:00 - N. Kumar (DIMA)

"Some generalization of Koszul property for diagonal subalgebras of bigraded algebras"

Abstract: For an ideal "I" of the polynomial ring K[x_1,...,x_n] generated be a regular sequence f_1,...,f_k of polynomials of degree "d". Then the (c,e)-diagonal subalgebra of standard bigraded Rees algebra is quadratic and Koszul under certain conditions for "c" and "e". I will talk about:
1. One can replace the Polynomial ring by Koszul Ring with same bounds and
2. For polynomial ring, the bounds can be improved
21 marzo 2012 - Aula 713 - Seminario di Algebra Geometria

ore 14:00 - Prof. A. Conca

"Ideals with linear powers"

21 marzo 2012 - Aula 714 - Seminario di (Sasso)
19 marzo 2012 - Aula 714 - Seminario (A. Perelli)

ore 17:00 - Prof. J.Kaczorowski (Univ. Poznan e Acc. Scienze Polacca)

"Twists of L-functions"

16 marzo 2012 - Aula 713 - Seminario (A. Perelli)

ore 17:00 - Prof. J.Kaczorowski (Univ. Poznan e Acc. Scienze Polacca)

"Twists of L-functions: applications"

15 marzo 2012 - Aula 715 - Seminario di Geometria e Fisica (Lanza)

ore 16:00 - Dott. Thomas-Paul Hack (Universitat Hamburg)

"On the consistency of classical and quantum supergravity"

14 marzo 2012 - Aula 713 - Seminario di Algebra Geometria (Rossi)

ore 14:00 - Prof. A. Conca

"Koszul algebras: another approach to the pinched Veronese (joint work with G.Caviglia)"

14 marzo 2012 - Aula 713 - Seminario (A. Perelli)

ore 15:00 - Prof. J.Kaczorowski (Univ. Poznan e Acc. Scienze Polacca)

"Solving linear equations in the extended Selberg class"

7 marzo 2012 - Aula 713 - Seminario di Algebra Geometria (Rossi)

ore 14:30 - Dott.ssa M. Mandal (IIT Bombay)

"On the Positivity of the Normal Chern Number of an ideal"

Abstract: In this talk we settle the positivity conjecture posed by Wolmer V. Vasconcelos. Let R be an analytically unrami&#64257;ed local ring with maximal ideal m and d = dimR > 0. If R is unmixed, then the normal Chern number of I is non negative for every m-primary ideal I in R.
2 marzo 2012 - Aula 713 - Seminario di (Sasso)

ore 14:00-16:00 - Dott. J. Agredo (Univ. de Chile)

"Entropy Production of Quantum Markov Semigroups, non-equilibrium and distances"

29 febbraio 2012 - Aula 713 - Seminario di Algebra Geometria (Rossi)

ore 16:30 - Dott.ssa M. Mandal (IIT Bombay)

"On the Negativity of the Chern number of an ideal"

Abstract: We present a solution to Vasconelos' negativity conjecture in certain unmixed quotient of regular local rings by explicit calculation of Hilbert polynomials of all ideals generated by system of parameters. We prove that the Chern number of a parameter ideal is non negative.
28 febbraio 2012 - Aula 716 - Seminario di Ottimizzazione - TdG (Pusillo)

ore 14:00 - M. Bianchi (Univ. Cattolica Sacro Cuore, Milano)

"Conditioning for optimization problems. Part I: the scalar case"

ore 15:00 - R. Pini (Univ. Milano Bicocca)

"Conditioning for optimization problems. Part II: the vector case"

21 febbraio 2012 - Aula 713 - Seminario di Algebra Geometria (Conca)

ore 14:30 - Min Nguyen Cong

"Polynomial bounds on the regularity"

21 febbraio 2012 - Aula 716 - Seminario di Ottimizzazione - TdG (Pusillo)

ore 14:30 - M. Sanguineti (Univ. Genova, Fac. Ingegneria)

"Suboptimal solutions to team optimization problems with stochastic information structure"

Abstract: Existence, uniqueness, and approximations of smooth solutions to team optimization problems with stochastic information structure are investigated. Suboptimal strategies made up of linear combinations of basis functions containing adjustable parameters are considered. Estimates of their accuracies are derived by combining properties of the unknown optimal strategies with tools from nonlinear approximation theory. The estimates are obtained for basis functions corresponding to sinusoids with variable frequencies and phases, Gaussians with variable centers and widths, and sigmoidal ridge functions. The theoretical results are applied to a problem of optimal production in a multidivisional firm, for which numerical simulations are presented.

ore 15:30 - G. Gnecco (Univ. Genova, Fac. Ingegneria)

"N-stage optimization via approximations of the policy functions"

Abstract: The approximation of the optimal policy functions is investigated for optimization problems with an objective that is additive over a finite number N of stages. The distance between optimal and suboptimal values of the objective functional is estimated, in terms of the errors in approximating the optimal policy functions at the various stages. Smoothness properties are derived for such functions and exploited to choose the approximating families. The approximation error is measured in the supremum norm, in such a way to control the error propagation from stage to stage. Nonlinear approximators corresponding to Gaussian radial-basis-function networks with adjustable centers and widths are considered. Conditions are defined, guaranteeing that the number of Gaussians (hence, the number of parameters to be adjusted) does not grow ``too fast'' with the dimension of the state vector. The results help to mitigate the curse of dimensionality in N-stage optimization. An example of application is given and the use of the estimates is illustrated via a numerical simulation.
14 febbraio 2012 - Aula 713 - Seminario di Algebra Geometria (Conca)

ore 14:30 - Tran Nam Trung

"On the asymptotic behavior the regularity of powers of ideals "

14 febbraio 2012 - Aula 716 - Seminario di Ottimizzazione - TdG (Pusillo)

ore 14:30 - A. Alessandri (Fac. Ingegneria, Univ. Genova)

"Controllo ottimo e predittivo per sistemi dinamici a parametri concentrati"

Abstract:

ore 16:00 - M.Gaggero (ISSIA CNR - Istituto di Studi sui Sistemi Intelligenti per l'Automazione)

"Controllo ottimo per sistemi a parametri distribuiti"

Abstract:
9 febbraio 2012 - Aula 714 - Seminario di Matematica Applicata (M. Piana)
11 gennaio 2012 - Aula 713 - Seminario di Algebra Geometria (Valla)

ore 14:30 - P. Mantero

"Liaison classes of non-licci ideals"

Abstract: A vast part of literature on CI-linkage has addressed questions relative to the most relevant, and well-behaved, class of ideals in linkage: licci ideals. However, for a non-licci ideal I, there are few results describing the structure of the linkage class of I.

In this talk we introduce a theoretical definition for `minimal' representatives in any even linkage class. We show that these ideals exist under reasonable assumptions on the linkage class, and, in general, if they exist they are essentially unique.
We then show that these ideals minimize homological invariants (e.g. Betti numbers, multiplicity, etc.) and they enjoy the best homological and local properties among all the ideals in their even linkage class. This justifies why they are, in some sense, the `best' possible ideals in the even linkage class.

We provide several classes of ideals that are the minimal representatives of their even linkage classes(including determinantal ideals) and, if time permits, show an easy application to produce more evidence towards the Buchsbaum-Eisenbud-Horrocks Conjecture.
9 gennaio 2012 - Aula 713 - Seminario di Algebra Geometria (Valla)

ore 14:30 - P. Mantero

"Squares of ideals and a Question of Vasconcelos"

Abstract: In the present talk we investigate a question stemming from a long-standing conjecture of Vasconcelos. Roughly speaking, the question under consideration asks: given an ideal I in a regular local ring R, does the Cohen-Macaulay property of both R/I and R/I^2 force R/I to be Gorenstein (under some technical assumtpions on I)?
The question was known to hold true in some instances, including height 2 perfect ideals and squarefree monomial ideals.
In this talk we prove it to hold true for several classes of ideals, including monomial ideals, and ideals defining algebras with low multiplicity.
However, in contrast with the previous results, we exhibit a prime ideal for which Vasconcelos' conjecture has a negative answer, showing that in general the answer cannot be positive, and proving the sharpness of our main result (the example lies in the first class of ideals not covered by our main result). This ideal is obtained by linkage as a deformation of the homogeneous ideal of 10 general points in P^5
13 dicembre 2011 - Aula 713 - Seminario di Algebra Geometria (Rossi)

ore 16:00 - L. Fouli, New Mexico State University (USA)

"Rees Algebras of square-free monomial ideals"

Abstract: We will discuss a construction that enables us to determine the defining equations of the Rees algebra for certain square-free monomial ideals generated in the same degree (at least 2) in a polynomial ring over a field. We also determine new classes of square-free monomial ideals that are of linear type. This is joint work with Kuei-Nuan Lin.

ore 17:00 - Phong Thieu Dinh, Osnabrueck University (Germany)

"On resonance varieties"

Abstract: In this talk, we study the irreducibility of resonance varieties of graded rings over an exterior algebra E with particular attention to Orlik-Solomon algebras. We prove that for a stable monomial ideal in E the first resonance variety is irreducible. If J is an Orlik- Solomon ideal of an essential central hyperplane arrangement, then we show that its first resonance variety is irreducible if and only if the subideal of J generated by all degree 2 elements has a 2-linear resolution. As an application we characterize those hyperplane arrangements of rank less than or equal to 3 where J is componentwise linear. Higher resonance varieties are also considered.
12 dicembre 2011 - Aula 714 - Seminario di Analisi Armonica (M. Spinelli)

ore 14:30 - R. Aramini

"Introduzione alla trasformata di Radon (quarta parte)"

ore 15:30 - M. Spinelli

"Moltiplicatori spettrali: il caso del Laplaciano"

9 dicembre 2011 - Aula 713 - Seminario di Algebra (Conca)

ore 15:00 - Ha Minh Lam - Institute of Mathematics Hanoi (Vietnam)

"Rees ring and Fiber cone of codimension two lattice ideals"

5 dicembre 2011 - Aula 705 - Seminario di Analisi Armonica (M. Spinelli)

ore 14:30 - R. Aramini

"Introduzione alla trasformata di Radon, terza parte"

ore 15:30 - M. Spinelli

"Calcolo funzionale olomorfo per semigruppi di diffusione, terza parte"

30 novembre 2011 - Aula 716 - Seminario di Matematica Applicata (M. Piana)

ore 16:00 - F. Delbary, Department of Informatics and Mathematical Modeling, Technical University of Denmark

"Inverse scattering in time domain"

Abstract: In the 90s, many reconstruction algorithms have been developed for imaging in the framework of Inverse Scattering in Frequency Domain; among others, the Point Source Method (PSM) and the Linear Sampling Method (LSM). Many improvements concerning these both algorithms have been achieved in the 2000s. Recently they have been adapted for Inverse Scattering in Time Domain, allowing better reconstructions. We propose to briefly explain the key points of the PSM and the LSM and then to show how the main ideas of these methods are extended in Time Domain.
24 novembre 2011 - Aula 710 - Seminario di Analisi Armonica (M. Spinelli)

ore 11:00 - M. Spinelli

"Calcolo funzionale olomorfo per semigruppi di diffusione (seconda parte)"

ore 12:00 - R. Aramini

"Introduzione alla trasformata di Radon (seconda parte)"

16 novembre 2011 - Aula 713 - Seminario (Perelli)

ore 14:30-15:30 - prof. Kaczorowski

"Results on the general Euler totient function"

15 novembre 2011 - Aula 427 - Seminario di CoCoA ()

ore 14:30 -

""

14 novembre 2011 - Aula 705 - Seminario di Analisi Armonica (M. Spinelli)

ore 14:30 - R. Aramini

"Introduzione alla trasformata di Radon (prima parte)"

Abstract: La trasformata di Radon e' uno strumento matematico di primaria importanza nell'ambito della diagnostica medica per immagini, in quanto descrive e formalizza una parte significativa dei processi di misura effettuati durante l'esame clinico noto come TAC, ed ispira l'algoritmo che consente la ricostruzione delle immagini desiderate (tipicamente, un insieme di sezioni del corpo umano) a partire dai dati.
Nel seminario saranno dunque richiamati gli elementi essenziali del problema della TAC e se ne presentera' una formalizzazione in termini di inversione di una trasformata di Radon. Verranno poi illustrate alcune analogie e differenze tra la trasformata di Radon e quella di Fourier, nonche' altre proprieta' notevoli e propedeutiche alle formule di inversione. Queste ultime saranno argomento di un seminario successivo.

ore 15:30 - M. Spinelli

"Calcolo funzionale olomorfo per semigruppi di diffusione"

Abstract: Nel seminario sara' affrontato il problema dei moltiplicatori spettrali mediante lo strumento del calcolo funzionale olomorfo. Verranno presentati e dimostrati alcuni risultati ottenuti negli ultimi decenni nel caso di operatori che generano semigruppi simmetrici di diffusione, tra i quali quelli conseguiti da M. Cowling e S. Meda.
7 novembre 2011 - Aula 714 - Seminario (Perelli)

ore 16:00 - J. Kaczorowski (Univ. Poznan)

"Multidimensional twists of L-functions of degree d with leading exponent 1/d"

4 novembre 2011 - Aula 711 - Seminario di Analisi Armonica (M. Spinelli)

ore 15:00 - R. Aramini

"Introduzione alla trasformata di Radon (prima parte)"

Abstract: La trasformata di Radon e' uno strumento matematico di primaria importanza nell'ambito della diagnostica medica per immagini, in quanto descrive e formalizza una parte significativa dei processi di misura effettuati durante l'esame clinico noto come TAC, ed ispira l'algoritmo che consente la ricostruzione delle immagini desiderate (tipicamente, un insieme di sezioni del corpo umano) a partire dai dati.
Nel seminario saranno dunque richiamati gli elementi essenziali del problema della TAC e se ne presentera' una formalizzazione in termini di inversione di una trasformata di Radon. Verranno poi illustrate alcune analogie e differenze tra la trasformata di Radon e quella di Fourier, nonche' altre proprieta' notevoli e propedeutiche alle formule di inversione. Queste ultime saranno argomento di un seminario successivo.

ore 16:00 - M. Spinelli

"Calcolo funzionale olomorfo per semigruppi di diffusione"

Abstract: Nel seminario sara' affrontato il problema dei moltiplicatori spettrali mediante lo strumento del calcolo funzionale olomorfo. Verranno presentati e dimostrati alcuni risultati ottenuti negli ultimi decenni nel caso di operatori che generano semigruppi simmetrici di diffusione, tra i quali quelli conseguiti da M. Cowling e S. Meda.
2 novembre 2011 - Aula 713 - Seminario di CoCoA ()

ore 14:30 -

""

2 novembre 2011 - Aula 427 - Seminario di CoCoA (Bigatti)
18 ottobre 2011 - Aula 713 - Seminario di Algebra Geometria (Perelli)

ore 14:30-15:30 - J.Pintz (Acc. Scienze Ungherese)

"On the twin prime conjecture"

17 ottobre 2011 - Aula 714 - Seminario di Algebra Geometria (Perelli)

ore 15:30-16:30 - J.Pintz (Acc. Scienze Ungherese)

"Exceptional Goldbach numbers and the Linnik-Goldbach problem"

7 ottobre 2011 - Aula 427 - Seminario di CoCoA (Bigatti)
29 settembre 2011 - Aula 427 - Seminario di CoCoA (Bigatti)
29 settembre 2011 - Aula 715 - Seminario di Analisi Armonica (M. Spinelli)

ore 11:00 - A. Carbonaro

28 settembre 2011 - Aula 713 - Seminario di CoCoA (Bigatti)
22 settembre 2011 - Aula 427 - Seminario di CoCoA (Bigatti)
20 settembre 2011 - Aula 713 - Seminario di Algebra Geometria (L. Badescu, G. Valla)

ore 15:00 - A. Beauville (Universite' de Nice)

"The L\"uroth problem and the Cremona group"

Abstract: The L\"uroth problem asks whether every field $K$ with $\mathbb{C}\subset K \subset \mathbb{C}(x_1,\ldots ,x_n)$ is of the form $\mathbb{C}(y_1,\ldots ,y_p)$.
After a brief historical survey, I will recall the counter-examples found in the 70's; then I will describe a quite simple (and new) counter-example.
Finally I will explain its relation with the study of the finite groups of birational automorphisms of $\mathbb{P}^3$.
1 luglio 2011 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 14:30 - C. De Zanet

"Struttura di contatto su gruppi di Carnot"

ore 15:30 - G. Alberti

"Mocklets, seconda parte"

22 giugno 2011 - - Seminario di Algebra Geometria (De Negri)
21 giugno 2011 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 11:00 - N. Botbol (Buenos Aires, Argentina)

"Implicit equations of rational hypersurfaces via free resolutions"

17 giugno 2011 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 14:30 - C. De Zanet

"Trasformazioni di Mobius e mappe conformi: teorema di Liouville e sue generalizzazioni"

ore 15:30 - G. Alberti

"Mocklets"

10 giugno 2011 - Aula 704 - Seminario di Matematica Applicata (Riccomagno)

ore 14:15 - L. di Scala (Novartis Pharma AG, IIS Translational Sciences)

"Case studies on designing adaptive clinical trials in oncology "

Abstract: The designs presented in this talk are motivated by real-life clinical situations in oncology drug development.
In the first design, a combination treatment (chemotherapy plus experimental compound XYZ) approaches Phase 3 of development with two different regimens/doses of XYZ.
Traditionally, regimen selection would be done by a Phase II study, followed by a separate phase III trial with the selected regimen.
In this talk, an adaptive, seamless phase 2/3 study is suggest instead.
This adaptive design encompasses both treatment selection as well as a confirmatory statistical test of superiority of the combination treatment over the single-agent control (i.e. chemotherapy).
Joint modeling of two time-to-event endpoints is used and flexible Bayesian predictive power tools drive the interim treatment selection.
Simulations show the operating characteristics and are used to compare selection rules and different methods of achieving alpha-level control for the superiority test.
In the second design, a novel, adaptive Bayesian time-to-dose limiting toxicity model is used to guide dose-escalation and determine the safe dose levels of an experimental combination therapy.
A Bayesian model is used to describe time to this toxicity event.
The posterior probabilities of a DLT from this model are used to determine the next tested dose in the the flexible dose-escalation process and assure a a proper quantification of the risks taken throughout the decision-making process.
7 giugno 2011 - Aula 715 - Seminario di Seminario IFM (Bartocci)
27 maggio 2011 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 14:30 - A. Ottazzi

"Tangenti ultrarigidi di gruppi nilpotenti sub-Riemanniani"

ore 15:30 - G. Mauceri

"Calcolo funzionale per l'operatore di Ornstein-Uhlenbeck"

26 maggio 2011 - Aula 705 - Seminario di Matematica Applicata (Riccomagno)

ore 14:00 - C. Dappiaggi (Department of Physics - Pavia)

"On higher spin fields and their quantization on curved backgrounds"

24 maggio 2011 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 15:00 - M. MANETTI (Univ. Roma La Sapienza)

"Ostruzioni e Semiregolarita'"

Abstract: Parlero' di un work in progress in collaborazione con Donatella Iacono.
Data una sottovarieta' localmente intersezione completa di una varieta' liscia proiettiva, sotto alcune ipotesi tecniche, si dimostra che tutte le ostruzioni alle deformazioni immerse sono annullate dall'applicazione di semiregolarita' di Bloch.
La dimostrazione utilizza il formalismo delle algebre di Lie differenziali graduate.
20 maggio 2011 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 14:30 - A. Ottazzi

"Tangenti ultrarigidi di gruppi nilpotenti sub-Riemanniani"

ore 15:30 - C. De Zanet

"Prolungamenti di algebre di Lie nilpotenti stratificate: teorema di Tanaka e applicazione allo studio delle strutture di contatto"

Abstract: Scopo del seminario e` illustrare alcuni risultati di Singer e Sternberg e successive generalizzazioni di questi dovute a Tanaka. Un'applicazione interessante di questi risultati interviene nello studio di mappe che preservano una data struttura geometrica: in particolare risolve il problema di rigidita` per gruppi di Carnot
16 maggio 2011 - Aula 714 - Seminario di Teoria dei Giochi (Gagliardo)

ore 14:30 - V. Fragnelli (Univ.Eastern Piedmont) - joint work with F. Briata (Univ. Pescara) and M. Dall'Aglio (Luiss Univ.)

"COLLUSION GAMES IN KNASTER PROCEDURE"

ore 15:30 - G. Pieri (Univ.Genova)

"ALGORITHMS AND EQUILIBRIA ON A CLASS OF OLIGOPOLY GAMES"

13 maggio 2011 - Aula 716 - Seminario di Analisi Armonica

ore 14:30 - A. Ottazzi

"Tangenti ultrarigidi di gruppi nilpotenti sub-Riemanniani "

Abstract: Scopo di questi seminari e' quello di raccontare un risultato recentemente ottenuto in collaborazione con Enrico Le Donne e Ben Warhurst, che mostra che il cono tangente non e' un invariante quasiconforme completo nella classe dei gruppi nilpotenti sub-Riemanniani.
Il nostro teorema dimostra tra l'altro che non vale il viceversa di un noto teorema di Margulis e Mostow che enunceremo.
Piu' esplicitamente, dimostriamo l'esistenza di un gruppo nilpotente dotato di una metrica sub-Riemanniana che non e' quasiconforme al suo cono tangente in un punto. Il risultato si fonda sullo studio di quei gruppi di Carnot, che diremo ultrarigidi, caratterizzati dal fatto che le uniche mappe quasiconformi sono traslazioni e dilatazioni.

Per arrivare ad enunciare il risultato e dare una traccia della dimostrazione, vedremo nel primo seminario un'introduzione agli argomenti fondanti. Daremo la definizione di cono tangente di Gromov per uno spazio metrico. Vedremo poi che almeno nel caso di gruppi di Lie dotati di una metrica sub-Riemanniana, il cono tangente coincide con un gruppo di Carnot (Teorema di Mitchell), che si puo' ottenere mediante una costruzione algebrica a partire dal gruppo di partenza. Questa costruzione e' nota come nilpotentizzazione e compare in un lavoro di Rothschild e Stein (1977) e in un altro di Nagel, Ricci e Stein (1990). Qui la nilpotentizzazione viene utilizzata per studiare un'ampia classe di operatori differenziali ipoellittici definiti su gruppi nilpotenti semplicemente connessi.

ore 15:30 - G. Mauceri

"Calcolo funzionale per l'operatore di Ornstein-Uhlenbeck"

12 maggio 2011 - Aula 705 - Seminario di Matematica Applicata (Riccomagno)

ore 14:00 - N. Pinamonti

"Introduction to quantum field theory on curved space-time"

29 aprile 2011 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 15:30 - G. Mauceri

"Calcolo funzionale per l'operatore di Ornstein-Uhlenbeck"

15 aprile 2011 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 14:30 - P. Sjogren (Goteborg University)

""

Abstract:

ore 15:30 - E. De Vito

"Introduzione alla meccanica quantistica, parte terza"

13 aprile 2011 - Aula 705 - Seminario di Teoria dei Giochi (Pusillo)
12 aprile 2011 - Aula 715 - Seminario di Teoria dei Numeri (A. Perelli)

ore 17:00 - J. Kaczorowski (Univ. Poznan')

"Converse theorems and twists of L-functions"

11 aprile 2011 - Aula 714 - Seminario di Teoria dei Numeri (A. Perelli)

ore 14:30 - J. Kaczorowski (Univ. Poznan')

"Some recent results on the global distribution of primes"

8 aprile 2011 - Aula 704 - Seminario di Teoria dei Numeri (A. Perelli)

ore 15:00 - Prof. C. Viola (Univ. Pisa)

"Misure d'irrazionalita` e di non-quadraticita` per logaritmi di numeri algebrici"

ore 15:50 - Prof. R. Dvornicich (Univ. Pisa)

"Funzioni di Newton che generano le funzioni simmetriche"

ore 16:40 - Prof. U. Zannier (Scuola Normale di Pisa)

"Irriducibilita' di Hilbert su alcuni gruppi algebrici"

4 aprile 2011 - Aula 715 - Seminario (A. Perelli)

ore 14:30 - Dott. G. Molteni

"Rappresentazione di interi in potenze di due: variazioni sul tema"

1 aprile 2011 - Aula 705 - Seminario di Analisi Armonica

ore 14:30 - G. Mauceri

"Analisi armonica Gaussiana"

ore 15:30 - E. De Vito

"Breve introduzione alla meccanica quantistica, parte seconda"

25 marzo 2011 - Aula 704 - Seminario di Algebra (Varbaro)

ore 11:00-12:00 - Nguyen Hop

"Something about toric face rings"

25 marzo 2011 - Aula 714 - Seminario di Matematica Applicata (Piana)

ore 15:00 - Sampsa Pursiainen, Acad. of Finland and Dip. Mat. Univ. Genova

"Accessible FEM for EEG and MEG with ZEFFIRO interface for brain imaging: mathematical basis and usage"

18 marzo 2011 - Aula 714 - Seminario di Matematica Applicata (Piana)

ore 15:00 - Sampsa Pursiainen, Acad. of Finland and Dip. Mat. Univ. Genova

"Conditionally Gaussian Hypermodels for Cerebral Source Localization"

4 marzo 2011 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 14:30 - M. Spinelli

"Il teorema dei moltiplicatori di Hormander"

G. Mauceri

"Il teorema massimale per misure di Radon"

15 febbraio 2011 - Aula 713 - Seminario di Algebra e Geometria (Badescu, Valla)

ore 14:30 - Andreas Rosenschon (Univ. Muenchen)

"Specialization of Chow groups"

11 febbraio 2011 - Aula 705 - Seminario di Analisi Armonica

ore 14:30 - L. Mantovani

"Decomposizioni in integrali diretti"

ore 15:30 - M. Spinelli

"H^1 e BMO"

9 febbraio 2011 - Aula 427 - Seminario di (De Vito)
4 febbraio 2011 - Aula 705 - Seminario di Analisi Armonica (Mauceri)

ore 14:30 -

"Quantum Stochastic Dynamic in Multi-photon System"

ore 15:30 - Micol Spinelli

"Introduzione alla teoria di Calderon-Zygmund III"

13 gennaio 2011 - Aula 427 - Seminario di Analisi Armonica (Mauceri)
11 gennaio 2011 - Aula 715 - Seminario di Fisica Matematica
7 dicembre 2010 - Aula 713 - Seminario di Algebra-Geometria (Beltrametti)

ore 15:00 - S. Verra (Univ. Roma Tre)

"La dimensione di Kodaira intermedia di alcuni spazi di moduli collegati alle curve"

Abstract: Nel seminario verranno presentati alcuni casi di spazi di moduli, collegati alle curve, che non sono ne' di tipo generale ne' di dimensione di Kodaira meno infinito.
Un primo caso interessante riguarda gli spazi di moduli S(g) delle coppie (C,L), dove C e' una curva di genere g e L una sua theta caratteristica pari. Verra' provato il seguente risultato, ottenuto in collaborazione con G. Farkas: la dimensione di Kodaira e' 0 per g = 8. Inoltre S(g) e' di tipo generale per g > 8, unirigato per g < 8.
22 novembre 2010 - Aula 713 - Seminario di CoCoA (Bigatti)
11 novembre 2010 - Aula 506 - Seminario (Pusillo)
14 ottobre 2010 - Aula 714 - Seminario di Fisica Matematica
13 ottobre 2010 - Aula 713 - Seminario di Analisi (Sasso)
5 ottobre 2010 - Aula 705 - Seminario di CoCoALib/Normaliz (Bigatti)
5 ottobre 2010 - Aula 713 - Seminario di Fisica Matematica
29 settembre 2010 - Aula 714 - Seminario di CoCoALib/Normaliz (Bigatti)
26 luglio 2010 - Aula 714 - Seminario (Riccomagno)
13 luglio 2010 - Aula 508 - Seminario di (De Vito)

ore 16:00 - D. Barbieri (Univ. Bologna)

"Un principio di indeterminazione per la corteccia visiva"

Abstract: La corteccia visiva primaria V1 incorpora informazioni sugli stimoli visivi attraverso un procedimento di analisi in multirisoluzione delle immagini catturate dalla retina. Oltre al dato di localizzazione spaziale, su V1 vengono memorizzate anche informazioni relative ad altre caratteristiche quali l'orientazione locale dei contorni, in una struttura classicamente definita a ipercolonne. Questa struttura e' codificata sul substrato bidimensionale della corteccia e, per quanto riguarda le orientazioni, la mappatura 2D scelta da molti mammiferi fra i quali l'uomo ha una disposizione caratteristica, detta di pinwheel, che e' stato possibile misurare con varie tecniche a partire dai primi anni 90. Sfruttando la geometria delle connessioni neurali, si mostrera' come sia possibile ottenere le principali proprieta' note della struttura a pinwheels utilizzando il principio di indeterminazione relativo al gruppo di Lie delle simmetrie coinvolte nella codifica delle orientazioni.
12 luglio 2010 - Aula 508 - Seminario di (De Mari)

ore 15:00-16:00 - D. Labate, Univ. Houston

"Analysis and identification of multidimensional singularities using directional multiscale representations "

Abstract: Recently introduced multiscale directional representations such as the curvelet and shearlet systems have been shown to be particularly effective at dealing with the set of singularities of multivariate functions and distributions. In this talk, we show that the shearlet transform provides a precise characterization of edge/boundary discontinuities of planar and solid regions. This investigation is motivated by applications in edge detection and feature extraction for 2D and 3D data. Some numerical demonstrations of such applications will be presented
8 luglio 2010 - Aula 714 - Seminario (Bigatti)

ore 10:00-11:00 - W. Seiler

7 luglio 2010 - Aula 714 - Seminario (Bigatti)
7 luglio 2010 - Aula 714 - Seminario (Bigatti)

ore 10:00-11:00 - W. Seiler

6 luglio 2010 - Aula 714 - Seminario (Bigatti)

ore 11:00:-12:00 - W. Seiler

6 luglio 2010 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 15:00 - Charles Weibel (Rutgers University, USA)

"Toric varieties, monoid schemes and resolution of singularities"

5 luglio 2010 - Aula 714 - Seminario (Bigatti)

ore 15:00-16:00 - W. Seiler

2 luglio 2010 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 14:30 - Werner M. Seiler (Inst. Math., Kassel University)

"Computational Commutative Algebra with Pommaret Bases"

Abstract:
22 giugno 2010 - Aula 713 - Seminario di Storia e Didattica (Borga, Furinghetti)

ore 16:00 - E. Barbin - Univ. Nantes

""

16 giugno 2010 - Aula 704 - Seminario di Matematica Applicata (Piana)

ore 15:00 - A. Sorrentino (DIMA)

"Random Sets of Neural Activity"

15 giugno 2010 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 14:30 - Manoj Kummini, Purdue University, USA

"Poset Embeddings of Hilbert Functions"

Abstract: Let R be a standard graded algebra over a field. We look at embeddings of the poset of Hilbert functions of ideals of R into the poset of ideals of R, as a way of classifying the possible Hilbert functions for ideals of R. This is joint work with G. Caviglia.

ore 15:45 - Ozeki Kazuho, Meiji University, Japan

"Hilbert coefficents of parameter ideals"

Abstract: The structure theorems of local rings are given in terms of the first Hilbert coefficients of parameter ideals. We also study the problem of when the Hilbert coefficients of parameters in a Noetherian local ring have uniform bounds, and when this is the case, to ask for their sharp bounds.
8 giugno 2010 - Aula 716 - Seminario di Matematica Applicata (Piana)

ore 14:30 - S. Massa - Dep. Stat. Sci., Univ.Padua

"Some recent advances on structural meta-analysis"

Abstract: Structural meta-analysis concerns combining information about relationships between variables from independent studies performed under partially comparable circumstances. After a brief introduction to graphical models, some types of combination of Gaussian graphical models, based on different use of the initial information, will be presented. Some algebraic interpretations will also be discussed.
7 giugno 2010 - Aula 706 - Seminario di Matematica Applicata
24 maggio 2010 - Aula 705 - Seminario di Analisi (Mauceri)

ore 16:00 - P. Sjogren - Univ. Goteborg

""

Abstract:
19 maggio 2010 - - Seminario
6 maggio 2010 - Aula 508 - Seminario di Analisi Armonica (Mauceri)

ore 11:00 - B. Franchi (Univ. Bologna)

"Forme differenziali nei gruppi di Carnot
"

Abstract: Sia G un gruppo di Carnot, cioe' un gruppo di Lie connesso, semplicemente connesso, stratificato e nilpotente.
Lo scopo di questo seminario e' quello di descrivere un complesso (E_0^*,d_c) di forme differenziali su G, introdotto da M. Rumin, che e', in senso opportuno, "naturale" per la struttura di gruppo.
Le classi di forme E_0^* sono sottoclassi delle usuali forme differenziali, mentre il "differenziale intrinseco" d_c \`e in generale un operatore di ordine >1 che tiene conto della non commutativita' del gruppo.
5 maggio 2010 - Aula 715 - Seminario di Analisi Armonica (Mauceri)

ore 16:00 - B. Franchi (Univ. Bologna)

"Forme differenziali nei gruppi di Carnot"

Abstract: Sia G un gruppo di Carnot, cioe' un gruppo di Lie connesso, semplicemente connesso, stratificato e nilpotente.
Lo scopo di questo seminario e' quello di descrivere un complesso (E_0^*,d_c) di forme differenziali su G, introdotto da M. Rumin, che e', in senso opportuno, "naturale" per la struttura di gruppo.
Le classi di forme E_0^* sono sottoclassi delle usuali forme differenziali, mentre il "differenziale intrinseco" d_c \`e in generale un operatore di ordine >1 che tiene conto della non commutativita' del gruppo.
28 aprile 2010 - Aula 706 - Seminario di Seminario /Lezione Rosolini

ore 14:30 - Rosolini

12 aprile 2010 - Aula 509 - Seminario di Teoria dei Giochi (Pusillo)
7 aprile 2010 - Aula 705 - Seminario di Algebra Geometria (Badescu)
17 marzo 2010 - Aula 705 - Seminario di Teoria delle Categorie (Pagnan)
16 marzo 2010 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 14:30 - Francesco Zucconi (Udine)

"Curve spin e teoria di Mori per il trigoglio di Del Pezzo"

ore 15:45 - Luke Oeding (Univ. of Florence)

"On the set-theoretic versions of conjectures of Holtz-Sturmfels and Landsberg-Weyman"

Abstract: A principal minor of a matrix is the determinant of a submatrix centered about the main diagonal. A basic linear algebra question asks to what extent is it possible to prescribe the principal minors of a matrix. We focus on the case of symmetric matrices.

The equations the algebraic variety of principal minors of symmetric matrices tell when it is possible for a given vector of length 2^n to be the principal minors of a symmetric n-by-n matrix. Holtz and Sturmfels found these equations in the cases n=3,4 and discovered an interesting connection to Cayley's hyperdeterminant. They conjectured that the hyperdeterminantal module generates the ideal of the variety.

Starting with examples using basic linear algebra I will describe some of the questions that motivated the original question and show some of the beautiful symmetry and geometry of this variety. Next I will sketch a proof of the set-theoretic version of the Holtz Sturmfels conjecture. Finally I will point out an unexpected connection to the tangential variety of the Segre product of projective spaces, and sketch a proof of a set-theoretic version of the Landsberg-Weyman conjecture.
9 marzo 2010 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 15:00 - Satoshi Murai

"Spheres arising from monomial ideals"

Abstract: In 1992 Thomas Bier introduced a suprisingly simple way to construct a large number of triangulations of spheres by using the Alexander duality of simplicial complexes. In this talk I will give a generalization of Bier's construction by using polarizations and the Alexander duality of monomial ideals, and discuss their algebraic and combinatorial properties.
3 marzo 2010 - Aula 710 - Seminario di Teoria dei Giochi (Pusillo)
23 febbraio 2010 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 15:00 - M. Aprodu (Bucharest)

"Koszul cohomology and algebraic geometry. III (ultima parte)"

Abstract: We present some recent developments of syzygy theory and applicationsof Koszul cohomology to the geometry of complex projective varieties. The series of talks will begin with a review of definitions and basic properties, and some examples. In the second talk we discuss vanishing/nonvanishing results and Voisin's description of Koszul cohomology in terms of Hilbert schemes. In the last talk, we present a proof of Green's conjecture for any smooth curve on an arbitrary K3 surface (joint work with G. Farkas). One of the consequences of this result is the fact that the minimal resolution of the homogeneous ideal of a projective K3 surface is completely determined by the Clifford index of a smooth hyperplane section.
The main bibliographical sources are the joint book with J. Nagel with the same title, published with the AMS (Univ. Lect. Series 52), and the preprint arXiv:0911.5310, joint with Gavril Farkas.
22 febbraio 2010 - Aula 704 - Seminario di Matematica Applicata (Piana)

ore 15:00-17:00 - L. Malag, airlab - Dip. Elettr. e Inf., Polit. Milano

"Towards the geometry of stochastic relaxation in pseudo-boolean function optimization"

Abstract: We analyze the problem of pseudo-Boolean function optimization by introducing the notion of stochastic relaxation, i.e., we find minima of f by minimizing its expected value over a set of probability densities. By doing this, the parameters of the statistical model become the new variables of the optimization problem.
We justify the use of the exponential family in the stochastic relaxation with previous results about the characterization of its topological closure and of the tangent space. We provide a characterization of the stationary points of the relaxed problem, together with a study of the minimizing sequences with reduced support. Finally, we show how stochastic relaxation can be interpreted as a unifying framework for the analysis of classical techniques in linear programming and stochastic optimization.
16 febbraio 2010 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 14:30 - G. Farkas (Humboldt Univ. Berlin)

"Maps between moduli spaces of curves and Gieseker-Petri divisors"

Abstract: We study contractions of the moduli space of stable curves beyond the minimal model of M_g, by resolving and giving a complete enumerative description of the rational map between two moduli spaces of curves, which associates to a curve C of genus g, the Brill-Noether locus of special divisors in the case this locus is a curve. As an application we give a lower bound for the slope of the cone of moving effective divisors on M_g.

ore 15:45 - M. Aprodu (Bucharest)

"Koszul cohomology and algebraic geometry. II
"

Abstract: We present some recent developments of syzygy theory and applicationsof Koszul cohomology to the geometry of complex projective varieties.The series of talks will begin with a review of definitions and basic properties, and some examples. In the second talk we discuss vanishing/nonvanishing results and Voisin's description of Koszul cohomology in terms of Hilbert schemes. In the last talk, we present a proof of Green's conjecture for any smooth curve on an arbitrary K3 surface (joint work with G. Farkas). One of the consequences of this result is the fact that the minimal resolution of the homogeneous ideal of a projective K3 surface is completely determined by the Clifford index of a smooth hyperplane section.
The main bibliographical sources are the joint book with J. Nagel with the same title, published with the AMS (Univ. Lect. Series 52), and the preprint arXiv:0911.5310, joint with Gavril Farkas.
12 febbraio 2010 - Aula 713 - Seminario di (Sasso)

ore 14:30 - Prof. Bassano Vacchini (Univ. Milano)

"Theoretical description of decoherence in interferometric experiments"

Abstract: Translation-covariant Markovian master equations used in the description of decoherence and dissipation are considered in the general framework of Holevo's results on the characterization of generators of covariant quantum-dynamical semigroups. A general connection between the characteristic function of a classical Levy process and loss of coherence for the center of mass degrees of freedom of a quantum system interacting through momentum transfer events with an environment is established. When the interplay with the internal degrees of freedom is relevant non-Markovian effects also arise. The relationship with both microphysical models and experiments is considered, focusing in particular on recent interferometric experiments exploring the boundaries between classical and quantum world.
9 febbraio 2010 - Aula 713 - Seminario di Algebra Geometria (Badescu)

ore 15:00 - MARIAN APRODU (Bucharest)

"Koszul cohomology and algebraic geometry. I"

Abstract: We present some recent developments of syzygy theory and applicationsof Koszul cohomology to the geometry of complex projective varieties.The series of talks will begin with a review of definitions and basic properties, and some examples. In the second talk we discuss vanishing/nonvanishing results and Voisin's description of Koszul
cohomology in terms of Hilbert schemes. In the last talk, we present a proof of Green's conjecture for any smooth curve on an arbitrary K3 surface (joint work with G. Farkas). One of the consequences of this result is the fact that the minimal resolution of the homogeneous ideal of a projective K3 surface is completely determined by the Clifford index of a smooth hyperplane section.
The main bibliographical sources are the joint book with J. Nagel with the same title, published with the AMS (Univ. Lect. Series 52), and the preprint arXiv:0911.5310, joint with Gavril Farkas.
20 gennaio 2010 - Aula 706 - Seminario (Piana)

ore 15:00 - Luigi Preziosi, Dip. Mat., Politec. Torino

"Aspetti meccanici di crescita tumorale"

Abstract: Il seminario esaminera' alcuni fenomeni in cui gli aspetti meccanici hanno un ruolo importante nella crescita tumorale. Le cellule tumorali vivono in un ambiente formato da altre cellule e da matrice extracellulare, interagendo con esse. Quando le cellule si duplicano e si muovono, si attaccano alla matrice extracellulare e la deformano, spostando le cellule intorno e rompendo e formando legami di adesione. Queste forze hanno una grandezza finita ed occorre introdurre il loro effetto nei modelli matematici per poter spiegare fenomeni quali l'inibizione da contatto, la compartimentalizzazione e l'invasione da parte delle cellule tumorali del tessuto circostante. Questo e' fatto sulla base della teoria delle configurazioni naturali multiple e della introduzione di stress e forze di soglia per il tensore degli sforzi e per le forze di interazione tra cellule e matrice extracellulare.
13 ottobre 2009 - Aula 704 - Seminario di Matematica applicata (Piana)

ore 16:00 - Matti S. Hamalainen

"Modeling of MEG and EEG: from Surface Mapping to Multimodal Imaging"

1 ottobre 2009 - Aula 705 - Seminario (Arezzo)

"Matematica: la scienza dei giovani"

29 luglio 2009 - Aula 704 - Seminario di (Riccomagno)

ore 10:30 - G. Pistone (Politecnico di Torino)

"Modelli esponenziali estesi"

ore 11:30 - A. Forcina (Universita` di Perugia)

"Indipendenze condizionate e modelli marginali"

Abstract:
17 luglio 2009 - Aula 713 - Seminario di (Covello)
9 luglio 2009 - Aula 704 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - J. MIGLIORE

"Pure O-sequences and Lefschetz properties"

Abstract:

ore 16:00 - C. WEIBEL

"The Grothendieck group of an affine cone"

Abstract: Let R be the homogeneous coordinate ring of a smooth projective variety X. We give an explicit description of the Grothendieck group of R, K_0(R).
The formula involves the Zariski cohomology of X with coefficients in Kahler differentials.
(This is joint work with Cortinas, Haesemeyer, Walker.)
23 giugno 2009 - Aula 713 - Seminario di (Sasso)

ore 14:00 - Power utility maximization under partial information

"We consider the power utility maximization problem under partial information. The underlying asset price process follows a continous semimartingale and strategies have to be constructed when only part of the information in the market is available. We show that this problem is equivalent to a new optimization problem, which is formulated in terms of observable processes.
We characterize the related value process as the unique bounded solution of semimartingale BSDE. "

17 giugno 2009 - Aula 508 - Seminario di Teoria delle Categorie (Pagnan)
4 giugno 2009 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 16:00 - C. Polini (University of Notre Dame)

"The interplay between cores, adjoints (or multiplier ideals) and algebraic properties of the Rees ring."

Abstract: In questa conferenza discutero' lavori eseguiti in collaborazione con Ulrich, con Kustin - Ulrich e dei risultati recenti della mia studentessa Angela Kohlhaas. Il problema affrontato e' il segente: Quando e' il core uguale all'aggiunto di una potenza di un ideale? Per ottenere quest'uguaglianza in particolare il core deve essere integralmente chiuso. E' tale condizione sufficente? Sia il core che l'aggiunto (or multiplier) di un ideale sono oggetti di centrale importanza per geometri algebrici e algebristi commutativi. Questi oggetti sorgono naturalmente in geometria birazionale (birational geometry) e nello studio dell'algebra di Rees.
28 maggio 2009 - Aula 711 - Seminario di Controllo dei Sistemi (Zolezzi)
27 maggio 2009 - Aula 716 - Seminario di Teoria dei giochi (Pusillo)

"Seminario studenti TdG"

26 maggio 2009 - Aula 713 - Seminario di Analisi armonica (Carbonaro)

ore 12 - Colin Guillarmou del Laboratoire J.A. Dieudonne di Nizza

"Riesz transform and multiplier theorem for Schrodinger operator on asymptotically Euclidean manifolds "

26 maggio 2009 - Aula 706 - Seminario di Analisi Armonica (Carbonaro)

ore 14:30 - Analisi armonica

26 maggio 2009 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - C. Pedrini

"Nikulin Involutions on K3 surfaces"

Abstract: We will discuss the results by Van-Geemen and Sarti on the explicit description for some classes of K3 surfaces (with Picard number 9) having a Nikulin involution and relate their
classification to Bloch-Beilinson and Murre's Conjectures on the Chow motive of the surface.
25 maggio 2009 - Aula 705 - Seminario di Teoria dei Giochi Ottimizzazione ed Applicazioni (Pusillo)

ore 15:00 - A.Ioffe - Dept. Math. Haifa (Israel)

"Subdifferential Calculus and Second Theorem of Welfare Economics"

Abstract: The talk will consist of three parts:
a) a description of a model for general theory of subdifferentials of nonconvex functions which captures many significant features common to individual theories of various specific subdifferentials;
b) a certain general "nonconvex separation theorem"
c) application of the latter for subdifferential characterization of Pareto optima in models of welfare economics. R. Lucchetti (Politecnico di Milano)

"New power indices and microarray games.
(joint paper with P.Radrizzani)"

Abstract: We define and we study new power indices, providing also a fat way to calculate them in weighted majority games. The main application is to microarray games in order to classify genes of people affected by a genetic disease. We compare some results obtained in this way with results present in the recent medical literature.
25 maggio 2009 - Aula 704 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - V. Bocci

""

Abstract:
20 maggio 2009 - Aula 705 - Seminario di Teoria delle Categorie (Pagnan)
13 maggio 2009 - Aula 705 - Seminario di Teoria delle Categorie (Pagnan)
8 maggio 2009 - Aula 713 - Seminario di Analisi Armonica (De Mari)
5 maggio 2009 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - P. ELLIA (Ferrara)

"Fibrati globalmente generati"

Abstract: Alcuni risultati recenti sulla classificazione dei fibrati generati dalle sezioni globali, con prima classe di Chern fissata, su uno spazio proiettivo ad n dimensioni.
5 maggio 2009 - Aula 715 - Seminario (Piana)

ore 16:00-17:00 - S. Pursiainen, Dep. Math., Helsinki Univ. of Techn.

"Bayesian inversion in EEG/MEG and Electrical Impedance Tomography (EIT) with FEM forward simulation"

Abstract: In this talk I will concentrate on numerical experiments in EEG/MEG and EIT in which Bayesian inversion together an FEM forward simulation were used.
Development of a solver for fully realistic model is also discussed.
28 aprile 2009 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:30 - C. Camere (Univ. Nizza)

"La stabilita' del fibrato tangente ristretto ad una curva"

27 aprile 2009 - Aula 705 - Seminario di Teoria delle Categorie (Pagnan)
27 aprile 2009 - Aula 704 - Seminario di Teoria dei Giochi Ottimizzazione ed Applicazioni (Pusillo)

ore 14:00-18:00 - S. Gagliardo

""

Abstract: F. Briata

"Essentializing Equilibrium Concepts"

Abstract: S. Villa

"Aspetti di programmazione dinamica nel problema dello scambio di reni"

Abstract: M. Lattarulo

"Indicatori bibliometrici per la misura dell'influenza intellettuale scientifica"

Abstract:
17 aprile 2009 - Aula 508 - Seminario di Gruppo Applicativo (De Vito)
8 aprile 2009 - aula 714 - Seminario di Algebra (Constantinescu)

ore 14:00 - A. Constantinescu

"Combinatorial secant varieties"

8 aprile 2009 - Aula 508 - Seminario di Teoria delle Categorie (Pagnan)
3 aprile 2009 - Aula 705 - Seminario di Seminario di Algebra (Varbaro)

ore 14:00 - M. Varbaro

"Combinatorial secant varieties"

2 aprile 2009 - Aula 508 - Seminario di Matematica Applicata (De Vito)

ore 16:00 - M. Piana (Univ. Verona)

"Considerazioni fisico-matematiche su un teorema in scattering inverso"

31 marzo 2009 - Sala conferenze DISI - Seminario di Genova, Torino, Milano Seminar: a Day on Commutative Algebra and Algebraic Geometry.

Pagina web

27 marzo 2009 - Aula 427 - Seminario di MRI

ore 10:00-12:00 - Piana

27 marzo 2009 - Aula 705 - Seminario di Algebra

ore 14:30 - Le Din Nham

25 marzo 2009 - Aula 714 - Seminario di Teoria dei Giochi (Pusillo)

"Il programma di simulazione di sistemi elettorali ALEX4 e sue applicazioni"

25 marzo 2009 - Aula 508 - Seminario di Teoria delle Categorie

ore 14:00-16:00 - R. Pagnan

17 marzo 2009 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - A. VAN TUYL (Lakehead University, Canada)

"Powers of cover ideals and their associated primes"

Abstract: Let G be a finite simple graph. The cover ideal of G is the monomial ideal J whose generators correspond to the minimal vertex covers of G.
In this talk, I will discuss my current project to understand the elements of Ass(R/J^s) with s>=2, that is, the set of associated primes. In particular, computer experiments have shown a link between colorings of the graph, the perfection of the graph, and the elements of Ass(R/J^s). I will also discuss a new algebraic way to calculate the chromatic number of a graph. This is joint work with C. Francisco and T. Ha.

ore 16:00 - Le Dung Trang, Direttore del Dipartimento di Matematica del ICTP (Trieste)

"Equisingularity Invariants"

Abstract: In this talk we shall define equisingularity and we shall search for algebraic invariants which define it. Often there is no way to compute them from the local ring of the singularity.
10 marzo 2009 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - F. GALLUZZI (Torino)

"Forme quadratiche e automorfismi di superficie K3 con numero di Picard 2"

Abstract: Utilizzando la teoria delle forme binarie, si dara' una descrizione del gruppo degli automorfismi delle superficie K3 generali aventi reticolo di Picard di rango 2. I risultati sono ottenuti in collaborazione con Giuseppe Lombardo e Chris Peters.

ore 16:00 - A. CONCA

"La proprieta' N_p per le algebre di Veronese"

Abstract: Lo studio delle equazioni che definiscono varieta' o anelli importanti e delle loro sizigie e' un problema centrale sia della algebra commutativa e della geometria algebrica. Green e Lazarsfeld hanno introdotto la proprieta' N_p per indicare la presenza di equazioni e sizigie, di ordine fino p, particolarmente semplici.
Lo scopo del seminario e' presentare alcuni risultati, ottenuti in collaborazione con W. Bruns e T. Roemer dell'universita' di Osnabrueck, che riguardano la proprieta' N_p per gli anelli di Veronese.
10 febbraio 2009 - Aula 714 - Seminario di Teoria dei Giochi (Pusillo)
30 gennaio 2009 - Aula 714 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - A. ROSENSCHON

"K_1 of Curves"

Abstract: We construct elements in K_1 of smooth projective curves over particular types of fields
15 gennaio 2009 - Aula 714 - Seminario di Teoria dei numeri (Perelli)

ore 14:30-16:30 - C. Viola (Pisa)

"Alcuni risultati classici di irrazionalita' e trascendenza"

23 dicembre 2008 - Aula 713 - Seminario (F. De Mari)

ore 15:00 - M. Cowling

"Isomorfismi di algebre di funzioni e isomorfismi di gruppi"

Abstract: Da tempo ci si e' chiesto se l'algebra di Fourier A(G) di un gruppo localmente compatto G, e le sue generalizzazioni A_p(G) (le algebre di Figa'-Talamanca e Herz), determinino il gruppo G. Propongo di presentare un panorama di vari risultati, a questo proposito, positivi e negativi, e faro' vedere che per i gruppi di Lie connessi, il problema assume un carattere piuttosto geometrico.
16 dicembre 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - B. BENEDETTI (Berlino)

"Knots, collapses and shellings"

Abstract: We start with the `collapse' notion and its interplay with concepts from algebraic combinatorics (like shellings) or topology (like deformation retracts). Any 2-dimensional simplicial complex that is homeomorphic to a ball, must be contractible, shellable and collapsible at the same time. What happens in higher dimensions was discovered by knot theorists in the Sixties: Surprisingly, the 3-balls with a knot in their 1-skeleton are (1) always contractible, (2) never shellable, (3) sometimes collapsible.
In a joint work with G. M. Ziegler, we used knots, collapses and shellings as peculiar tools to understand an open problem from quantum physics.
16 dicembre 2008 - Aula 713 - Seminario di Modelli Matematici (Pusillo)
10 dicembre 2008 - Aula 713 - Seminario di Teoria dei numeri (Perelli)

ore 14:30-15:30 - J. Kalpokas (Univ. Vilnius)

"Sum of a Dirichlet L-function over the non-trivial zeros of another Dirichlet L-function"

18 novembre 2008 - Aula 713 - Seminario di Algebra-Geometria (Beltrametti)

ore 15:00 - F. Flamini

"Schemi di Hilbert di scroll di genere g"

Abstract: In questo seminario voglio presentare alcuni recenti ricerche in collaborazione con
A. Calabri, C. Ciliberto e R. Miranda, riguardanti lo studio degli schemi di Hilbert parametrizzanti
scroll (i.e. superfici rigate in rette) non singolari di genere (sezionale g) e grado d, che sono linearmente
normali nel loro span proiettivo.

Se il tempo lo permette, vorrei anche discutere alcune connessioni con le degenerazioni di superfici
cosiccome con le possibili applicazioni allo studio degli spazi di moduli di fibrati di rango 2 e grado d su
una curva liscia di genere g.
12 novembre 2008 - Aula 713 - Seminario di Teoria dei numeri (Perelli)

ore 14:30-15:30 - prof. J. Kaczorowski (A.Mickiewicz Univ., Poznan)

"Universality of periodic L-functions"

7 novembre 2008 - Aula 715 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - M. Roggero (Torino)

"Ideali con fissato ideale iniziale e schemi di Hilbert"

Abstract:
5 novembre 2008 - Aula 713 - Seminario di Teoria dei numeri (Perelli)

ore 14:30-15:30 - prof. J. Kaczorowski (A.Mickiewicz Univ., Poznan)

"Distribution of irreducible algebraic integers"

23 ottobre 2008 - Aula 508 - Seminario (Perelli)

ore 10:00-11:00 - A. Lucchini (Univ. Padova)

"La funzione zeta probabilistica nei gruppi finiti e profiniti"

22 ottobre 2008 - Aula 713 - Seminario (Perelli)

ore 14:30-16:00 - A. Lucchini (Univ. Padova)

"Funzioni zeta nei gruppi e negli anelli"

21 ottobre 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - N. SEMENOV (Monaco)

"Motivic invariants of algebraic varieties with applications to algebraic groups"

Abstract: Norm varieties and varieties with special correspondences play an important role in proof of the Bloch Kato conjecture by M. Rost and V. Voevodsky.
In the talk we introduce these classes of varieties, explain relations between them, and give some surprising applications to the theory of algebraic groups.

ore 16:00 - D. HERNANDEZ RUIPEREZ (Salamanca)

"Moduli spaces of semistable sheaves on singular genus 1 curves"

Abstract: We &#64257;nd some equivalences of the derived category of coherent sheaves on a Gorenstein genus one curve that preserve the (semi)-stability of pure dimensional sheaves. Using them we establish new identi&#64257;cations
between certain Simpson moduli spaces of semistable sheaves on the curve. For rank zero, the moduli spaces are symmetric powers of the curve whilst for positive rank there are only a &#64257;nite number of non-isomorphic spaces. We prove similar results for the relative semistable moduli spaces on an arbitrary genus one &#64257;bration with no conditions either on the base or on the total space. For a cycle of projective lines, we compute all the stable sheaves of degree 0 Finally, we prove that the connected component of the moduli space that contains vector bundles of rank r is isomorphic to the r-th symmetric product of the rational curve with one node.
20 ottobre 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - K.N. RAGHAVAN (Chennai)

"A KRS Basis for rings of invariants"

Abstract: We give a basis for the ring of multilinear GL(V) invariant functions of n-fold product of End(V) (where V is a finite dimensional complex vector space), discuss applications to other rings of invariants such as that of polynomial invariants of several tensors, and outline a proof via Hecke algebras, Kazhdan-Lusztig cell modules and the Gram determinant.

ore 16:00 - L. SOLA CONDE (Madrid)

"Varieties swept out by grassmannians of lines"

Abstract: Classifying projective varieties containing special subvarieties is a classical problem in Algebraic Geometry. As a part of a joint project with R. Munoz, I will address the problem of characterizing grassmannians of lines by containing grassmannians of lines in codimension 2, under certain assumptions.
14 ottobre 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - F. CAMPANA (Nancy)

"Nilpotent quotient of Kaehler group"

Abstract: The torsion-free nilpotent quotients of the fundamental group of a compact Kaehler manifold X (in particular: of complex projective manifolds) can be computed from its Albanese map.
Hodge theory also permits to show tha if two generic points of X can be joined by a chain of subvarieties with (normalisations having) fundamental groups either finite, solvable or nilpotent of nilpotency class r, then the fundamental group of X itself has (virtually) the corresponding property. All statements fail in general without the Kaehler assumption.
3 ottobre 2008 - Aula 713 - Seminario di Analisi armonica (De Mari - Mencattini -De Vito)

"Analisi Armonica sui gruppi
semisemplici"

26 settembre 2008 - Aula 713 - Seminario di Analisi armonica (F. De Mari)

ore 14:30 - F. Zizzi

"Discussioni su: "An Introduction to Harmonic Analysis on Semisimple Lie Groups" di Varadarajan"

23 settembre 2008 - aula 716 - Seminario

ore 14:30 - Radu Ioan Bot, University of Chemnitz (Germany)

"Conjugate duality in convex optmization. Theoretical aspects
and some applications in machine learning"

16 settembre 2008 - Aula 713 SEMINARIO ANNULLATO - Seminario di Algebra-Geometria (Beltrametti)

ore 15:00 - Y. KAWAMATA

"Minimal model program and semi-orthogonal decomposition of derived categories

"

Abstract: Bondal and Orlov found a close parallelism between the
operations in the minimal model program and the
semi-orthogonal decompostions of bounded derived
categories of coherent sheaves.
We consider its extension to some singular varieties,
toric varieties and 3-dimensional varieties with terminal
singularities.
15 settembre 2008 - Aula 508 - Seminario di Analisi Armonica (Mencattini)

ore 15:00 - Prof. Veeravalli VARADARAJAN (UCLA)

"Some General Remarks on Harmonic Analysis on Semisimple Lie Groups"

11 settembre 2008 - Aula 714 - Seminario di Teoria dei numeri (perelli)

ore 14:30 - prof R.Balasubramanian (Madras)

"Sumfree sets in finite abelian groups"

15 luglio 2008 - Aula 713 - Seminario di Algebra Geometria

ore 15:00 - A. KNUTSEN

"Sull'autointersezione di curve mobili e costanti di Seshadri

"

Abstract: Illustrero' un metodo per dare un bound inferiore sull'autointersezione delle curve
in una famiglia di curve che ricoprono una superficie liscia S e con un punto di molteplicita' m.
Il bound dipende dalla positivita' di K_S. In particolare, come applicazione, dimostrero' che se la
costante di Seshadri di un line bundle L su una superficie liscia in un punto generale e' bassa,
allora la superficie' e' fibrata in curve di grado basso rispetto ad L (lavoro in collaborazione
con T. Szemberg e V. Syzdek).
8 luglio 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 11:45 - Chiara Brambilla, Universita` di Roma (I)

"VARIETA' DI SECANTI E METODO DEGLI ORAZI"

Abstract: Lo studio delle varieta' di secanti superiori di varieta' proiettive ha attratto molta attenzione, sia nell'ambito della geometria classica, sia recentemente, ed e' connesso, tra l'altro, al problema dell'interpolazione polinomiale e al problema di Waring polinomiale.
Un risultato fondamentale in questo ambito e' il teorema di Alexander e Hirschowitz, che riguarda il caso delle varieta' di Veronese. Alexander e Hirschowitz hanno utilizzato il linguaggio degli schemi zero dimensionali e hanno introdotto la cosiddetta tecnica degli Orazi differenziale.
Nel mio seminario descrivero' le idee principali alla base della dimostrazione del teorema di Alexander-Hirschowitz e ne daro' alcune applicazioni, in particolare al caso di varieta' di Segre-Veronese.
(Lavori in collaborazione con Giorgio Ottaviani e Hirotachi Abo)

ore 15:00 - Luca Ugaglia, Politecnico di Torino

"Sulle varieta` di Veronese nelle Grassmanniane"

3 luglio 2008 - Aula 713 - Seminario di Analisi armonica

ore 15:30 - Andrew Morris

"Tent spaces "

16 giugno 2008 - Aula 713 - Seminario di Teoria dei Giochi (Pusillo)

ore 14:30 -

"Weighted average lexicographic values for share sets and balanced cooperative games"

Abstract: The average lexicographic value (AL value) is introduced in Tijs 2005 for balanced games.
It is, in an n-player situation, the average of the n! lexicographic maxima of the core corresponding to the n! orderings of the players. The idea was extended in Caprari and al. 2006 for share opportunity sets. Much emphasis is there on the continuity properties of the AL-value on compact convex share sets and especially for perfect share sets. Inspired by the literature on weighted Shapley values (Kalai and al. 1988, Shapley 1953 we became interested in the existence of weighted AL-values. At first sight, there are two approaches to define weighted lexicographic values. On one hand, one on can put weights on orderings of the players leading to mixed lexicographic values. On the other hand, one can have weights on the players or a hierarchical weight system on the players leading to weighted lexicographic values.

ore 15:15 -

"Sublinear separation and nonconvex duality in consumer theory"

Abstract: Closed radiant (star-shaped at the origin) sets are characterized by means of separation
properties which are completely analogous to those which hold for convex sets containing the origin, the only difference being that the separating functions are superlinear instead of linear. Namely a set A of a normed space X is closed and radiant if and only if for every point x not belonging to A, there exists a continuous superlinear function s on X such that s(x) > 1 and s(a) _ 1 for every a in A. In the same vein, a set B _ X is closed and coradiant (complement of radiant) if and only if for every x /2 B, there exists a continuous sublinear function p : X ! R such that p(x) < 1 and p(b) _ 1 for all b 2 B.
Exchanging strict and weak inequalities in the above relations we obtain the definition of an evenly radiant set A and the one of an evenly coradiant set B and these can be characterized by means of their tangent cones.
These separation properties allow to extend a number of concepts and results about quasiconvex and quasiconcave functions to the study of the functions whose lower level sets are radiant, i.e. those which are nondecreasing along every rays starting from the origin.
We call such functions radiant.
We concentrate in particular on the relations between the direct utility function u and the indirect utility function v(p) = sup{u(x) : p(x) _ 1}, defined on the set P of all sublinear
pricing systems. These relations are based on a conjugation scheme in which the space X is paired with P, rather than the dual space X0.
We discuss the assumptions under which u coincides with its biconjugate
(the conjugate of v) and prove that this holds under very weak assumptions,
which involve no convexity.

ore 16:15 -

"Game theory and applications: a truly dirty job"

Abstract: Like in a chat around fire, I will discuss with you some of my recent work in the applied field (medicine, natural resources, industrial organization), emphasizing some of the difficulties which arise when one tries to put the formal tools at work.
10 giugno 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - M. SPITWECK

"Motivic Landweber Exactness"

Abstract: We show how Landweber's exact functor theorem can be utilized in motivic homotopy theory to obtain new motivic spectra. We also describe slices in the sense of Voevodsky of such spectra referring to the "conjectural" slices of algebraic cobordism spectrum.
6 giugno 2008 - Sala Riunioni 427 - Seminario di Statistica Matematica (Rogantin)

ore 15:00 - G. Pistone

3 giugno 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - C. BERTOLIN

"Morfismi multilineari tra 1-motivi"

Abstract: Introduciamo la nozione di biestensione di 1-motivi su uno schema qualsiasi S. Definiamo i morfismi bilineari tra 1 motivi come classi di isomorfismi di tali biestensioni. Nel caso in cui S sia lo spettro di un campo di caratteristica 0, verifichiamo che queste biestensioni forniscono morfismi bilineari tra le realizzazioni degli 1 motivi.

ore 16:00 - J. AYOUB

"We determine all the natural transformations H*()->H^*() where H^*:DM(k)->D(\Q) is singular cohomology of motives."

29 maggio 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - K. ZAINOULINE

"Special correspondences and Chow traces of Landweber-Novikov operations"

Abstract: We prove that the function field of a variety which possesses a special correspondence in the sense of M. Rost preserves the rationality of cycles of small codimensions.
This fact was proven by Vishik in the case of quadrics and played the crucial role in his construction of fields with $u$-invariant $2^r+1$.
The main technical tools are algebraic cobordism of Levine-Morel, generalized Rost degree formula and divisibility of Chow traces of certain Landweber-Novikov operations.
As a direct application of our methods we prove the Vishik's Theorem for all $F_4$-varieties.
22 maggio 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - Cartwright

"Hilbert schemes of 8 points"

Abstract: The Hilbert scheme of points parametrizes closed 0-dimensional subschemes of affine space.
For many points in 3 or more dimensions, the Hilbert scheme is reducible. In particular, for 8 points in 4-space, there are exactly two components. Furthermore, the equations defining each component can be described explicitly.
20 maggio 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - G. CASNATI

"The Gorenstein Locus of the Punctual Hilbert Scheme"

Abstract: Let Hilb_d(P^N) be the Hilbert scheme parametrizing subschemes of P^N of degree d.
It has been proved very recently that it is irreducible for d&#8804;7 and that it is always reducible for d&#8805;8 and N&#8805;4.
Now we focus our attention on the Gorenstein locus Hilb_d^G (P^N) of Hilb_d(P^N), i.e. the open locus parametrizing Gorenstein subscheme. In a very recent paper by R. Notari and myself, we prove that Hilb_d^G (P^N) is irreducible for d&#8804;9.
We also study its singularities giving their complete geometric characterization when d&#8804;8.
14 maggio 2008 - Aula 713 - Seminario di Algebre di Lie (Venturi)
8 maggio 2008 - Aula 508 - Seminario

ore 17:00 - Gaetano Zampieri (Dip. Informatica, Univ. Verona)

"Sulla congettura Jacobiana di Keller"

Abstract: Uno dei 18 problemi della lista nell'articolo di Steve Smale "Mathematical problems for the next century" (The Mathematical Intelligencer 20, 7-15, 1998) consiste nel provare o dare un controesempio alla Congettura Jacobiana di Keller: una funzione polinomiale con determinante Jacobiano diverso da 0 e un automorsmo polinomiale (e cioe' bigettiva e con inversa polinomiale). Nel seminario si illustrano alcuni fatti fondamentali sulla questione, in particolare la riduzione del problema ai polinomi cubici. A partire poi da un recente esempio di de Bondt, si introduce il concetto di invariante omogeneo e un problema aperto che potrebbe essere un passo nella direzione di un possibile controesempio alla Congettura Jacobiana.
7 maggio 2008 - Aula 713 - Seminario di Algebre di Lie (Venturi)
6 maggio 2008 - Aula 716 - Seminario di Geometria e Fisica (Mencattini)

ore 14:30 - E. De Vito

"Ricostruzione di segnali sparsi: minimizzazione l_1+l_2"

6 maggio 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - JOSE CARLOS SIERRA GARCIA

"Una limitazione inferiore del grado di un fibrato vettoriale globalmente generato"

Abstract: Sia E un fibrato vettoriale globalmente generato di rango maggiore o uguale a due su una varieta' complessa, ridotta e irriducibile. In questo seminario si presenta una limitazione inferiore del grado di E. Come corollario, per sottovarieta' della Grassmanniana G(k,N), si ottiene sia una limitazione inferiore del loro grado, sia una classificazione di quelle di grado minimo nello spirito dei risultati classici di Del Pezzo e di Bertini. Infine, si mostra che le sottovarieta' normali di G(k,N) di grado minore o uguale a N (che sodisfano anche una certa condizione tecnica) sono semplicemente conesse, in linea con un recente risultato di P. Ionescu per sottovarieta' dello spazio proiettivo.
5 maggio 2008 - Aula 714 - Seminario di Teoria dei Giochi (Pusillo)
29 aprile 2008 - Aula 716 - Seminario di Geometria e Fisica (Mencattini)

ore 16:15 - Gianni Cassinelli (DIFI)

"Rappresentazioni unitarie di supergruppi di Lie in superspazi di Hilbert"

Abstract: Viene data una definizione precisa di rappresentazione unitaria di un suprgruppo di Lie (in un superspazio di Hilbert) e viene descritta una proprieta' fondamentale di queste rappresentazioni.
Viene definita la rappresentazione indotta da una rappresentazione di un sottogruppo "speciale" (opportunamente definito) e viene descritta una generalizzazione del Teorema di Imprimitivita' di Mackey per questa situazione. Infine viene brevemente descritto come possano essere classificate le rappresentazioni irriducibili di una classe di superprodotti semidiretti che include le estensioni supersimmetriche del gruppo di Poincare.
22 aprile 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - J. CARAVANTES

"On the Picard group of low codimension subvarieties"

Abstract: Given a complex smooth closed subvariety X of a smooth projective variety Y. Many well known results support the idea of a "heredity" of geometrical properties, so that some geometrical aspects of X are highly determined by Y. In this background, we introduce a method to determine if n-dimensional smooth subvarieties of an ambient space of dimension at most 2n &#8722; 2 inherit the Picard group from the ambient space (as it happens when the ambient space is a projective space, according to results of Barth and Larsen).
This method has been used to give an affirmative answer (up to some mild natural numerical conditions) when the ambient space is a Grassmannian of lines (thus improving results of Barth, Van de Ven and Sommese) or a product of two projective spaces of the same dimension.
15 aprile 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - C. Arezzo

"Metriche di curvatura costante e flusso di Ricci su varieta' algebriche"

Abstract: In particolare presentero' una nuova costruzione di metriche a curvatura costante su scoppiamenti (in collaborazione con F. Pacard), gli effetti dei risultati di Perelman nel caso complesso e come questi permettano di affrontare con piu' ottimismo alcuni problemi classici sul legame tra metriche a curvatura costante e stabilita' algebrica della varieta'.
Tempo permettendo daro' la traccia di un'estensione di questi risultati al caso di deformazioni di varieta' e delle sue conseguenze, ottenuta in collaborazione con G. La Nave.

ore 16:00 - H. Kurk

"Towards a higher dimensional Kricever correspondence"

Abstract: Spectral data of germs of linear diff. operators can be oeganized into a geometric object, in 1 variable case: an algebraic curve C (representing Eigenvalues) and a holomorphic vector bundle on C (corresponding Eigenspaces). Deforming operators preserving C leads to "isospectral deformations" of operators, which are governed by a system of differential equ. ("KP-Hierarchy"). We intend to study higher dim. analogues of this fascinating picture. Part of this program is to represent spectral data as
points in some infinite dim. Grassmannian (Krichever correspondence).
I will explain a 2-dim. analogue of this (joint work with D. Osipov and A. Zheglov). We invented a kind of geometric objects, called "formal ribbons", which are slight generalizations of formal schemes which locally look like formal completions of a surface along a curve. On the one hand, they contain as a full subcategory pairs (X,C) (ample integral curve C on a smooth surface X), on the other hand they are in 1-1 correspondence to points of a certain Grassmannian.
15 aprile 2008 - Aula 711 - Seminario di Teoria dei Giochi (Pusillo)

ore 14:30 - Theo Driessen (Twente University at Enschede)

"A weighted pseudo-potential approach to values for TU games"

Abstract: The paper provides a twofold generalization of the well-known characterization of the Shapley value for TU games as the discrete gradient of a so-called potential function.
On the one hand the potential approach is extended to the so-called weighted pseudo-potential approach in the sense that the extended representation may incorporate, besides a fraction of the discrete gradient, a fraction of the underlying pseudo-potential function itself, as well as a fraction of the average of all the components of the gradient. On the other hand the paper fully characterizes the class of values for TU games that admit a weighted pseudo-potential representation. Besides two individual constraints, these values have to be efficient, symmetric, and linear. The theory developed is illustrated by several examples of such values and their weighted pseudo-potential representations are discussed.
8 aprile 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - V. Ancona

"Bochner-Martinelli formulas on singular complex spaces"

8 aprile 2008 - Aula 705 - Seminario (Piana)

ore 15:00 - Erkki Somersalo (Department of Mathematics, Helsinki)

"Hypermodels and qualitative information in imaging"

Abstract: In imaging applications, the typical problem is to reconstruct or recover an image based on incomplete, noisy and indirect information. The problem has all the typical characteristics of ill-posed inverse problems, such as non-uniqueness of the solution and high sensitivity to noise. To obtain a reasonable solution, the data have to be augmented by complementary information that is imported into the reconstruction algorithm either by classical regularization or recasting the problem in a statistical framework.
Since often the complementary information is qualitative, it needs to be translated into a quantitative form before it can be used in the deterministic approach. In the Bayesian approach presented in this presentation, we show how hierarchical models provide a flexible framework for interpreting qualitative prior information, leading to effective numerical algorithms. Moreover, the approach allows the estimation of the credibility of the estimates, a feature that is particularly important in many medical imaging applications.
2 aprile 2008 - Aula 705 - Seminario di Geoemtria e Fisica (Mencattini)

ore 14:30 - A. Perelli

"Funzioni L, II: Riemann e Dirichlet"

1 aprile 2008 - Aula 716 - Seminario di Geoemtria e Fisica (Mencattini)

ore 14:30 - P. Polesello (Padova)

"Equivalenze di Morita per DQ-algebroidi"

Abstract: Il problema della quantizzazione per deformazione delle varieta' complesse porta naturalmente a sostituire le algebre in gioco con degli algebroidi (= algebre con piu' oggetti). Nel caso delle varieta' di contatto complesse, l'esistenza di un algebroide di deformazione quantizzazione (= DQ-algebroide) e' stata provata nel 1996 da Kashiwara. Nella prima parte di questo seminario richiamero' tale risultato e mostrero' come la classificazione dei DQ-algebroidi su una varieta' di contatto complessa sia data da un certo gruppo di coomologia. Nella seconda parte (frutto di una collaborazione con A. D'Agnolo) mostrero' che per i DQ-algebroidi le equivalenze di Morita coincidono con le equivalenze lineari e che la classificazione dei DQ-algebroidi a meno di tali equivalenze sia data da un secondo gruppo di coomologia.
1 aprile 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - A. Del Padrone

"Funzioni formali in geometria proiettiva"

Abstract:
28 marzo 2008 - Aula 713 - Seminario (Riccomagno)

ore 15:00 - Wynn

"incontro informale su disegni ottimi"

ore 16:00 - F. Rapallo

"Adjacent minors and contingency tables"

27 marzo 2008 - Aula 713 - Seminario di Teoria dei Giochi (Pusillo)
19 marzo 2008 - Aula 509 - Seminario di Geoemtria e Fisica (Mencattini)

ore 14:30 - A. Perelli

"Funzioni L, I: Riemann e Dirichlet"

18 marzo 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - L. BONAVERO

"On fiber space containing quasi-lines"

Abstract:

ore 16:00 - A. ROSENSCHON

"The modified Ceresa cycle modulo q"

Abstract: We construct examples of smooth projective varieties over p-adic fields for which the Chow group of codimension 2 cycles modulo q is infinite
11 marzo 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

Pagina web

ore 14:30 - L. BADESCU

"Un approccio geometrico alle complete intersezioni insiemistiche"

Abstract: Il seminario ha un carattere piuttosto informale. Usando la teoria di
Grothendieck-Lefschetz si trovano delle condizioni necessarie affinche' una
data sottovarieta' di uno spazio proiettivo P^n sia completa intersezione insiemistica in P^n. Si illustrano i risultati attraverso alcuni esempi.

ore 16:00 - L. ROBBIANO

"Giacimenti petroliferi e schemi di Hilbert"

Abstract: see PDF
11 marzo 2008 - Aula 716 - Seminario di Geoemtria e Fisica (Mencattini)

ore 14:30 - Carlo Mazza

"Un'introduzione ai motivi"

Abstract: La teoria dei motivi e' nata da un'idea di Grothendieck negli anni 60 e si e' sviluppata negli anni fino agli ultimi risultati di Voevodsky.
Esporremo la teoria di base per le varieta' lisce e proiettive e faremo una breve panoramica delle applicazioni in diversi campi.
6 marzo 2008 - Aula 508 - Seminario

ore 17:00 - M. Piana

"Metodi computazionali in imaging medico e neuroscienze"

4 marzo 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - B. HARBOURNE

"Seshadri constants and symbolic powers"

Abstract: I will discuss recent work related to a question of Craig Huneke.
Huneke asked if J^2 contains J^(3)whenever J is a radical ideal defining a finite subscheme of P^2. I will suggest a generalization for P^N. In case J defines a finite set of generic points I will relate the problem to Seshadri constants and outline an approach to a proof.
(In case N=2, the approach works and thus J^2 contains J^(3) whenever J is a radical ideal defining any finite set of generic points of P^2.)

ore 16:00 - M. KREUZER

"Exact and Approximate Border Bases"

Abstract: After introducing the concept of border bases and their fundamental properties, we study their syzygy modules.
We explain the border basis versions of Buchberger's criterion and the theorem of Schreyer. Then we apply these results to the approximate setting where we define approximate border bases and illustrate their good numerical behaviour.
4 marzo 2008 - Aula 716 - Seminario di Geoemtria e Fisica

ore 14:30 - Giacomo Monti Bragadin (DIMA)

"TEORIA CLASSICA DELLE FORME AUTOMORFE:UN'INTRODUZIONE (Parte II)"

Abstract: Riepilogo essenziale su superficie di Riemann e gruppi fuchsiani
Costruzione delle serie di Poincare' come introduzione alla
definizione di funzioni e forme automorfe
Corrispondenza tra k-forme automorfe e differenziali di peso k sulla
corrispondente superficie di Riemann;divisori;
teorema di Riemann-Roch
Spazio di Hilbert delle forme cuspidali;dimensione degli spazi
vettoriali delle forme regolari e delle forme cuspidali
Esempi vari
Cenni a possibili generalizzazioni
26 febbraio 2008 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - F. Tovena

"Immersione di sottovarieta' e teoremi dell'indice per applicazioni olomorfe"

Abstract: (lavoro in collaborazione con M. Abate e F. Bracci) Sia S una sottovarieta' complessa liscia di una varieta' complessa liscia M. Si descrivono alcune classi coomologiche che permettono di paragonare l'immersione di S in M con l'immersione di S come sezione nulla nello spazio totale del fibrato normale.
Si forniscono inoltre alcune applicazioni valide nel caso di annullamento di tali classi coomologiche.
21 febbraio 2008 - Aula 713 - Seminario di Teoria dei Giochi (Pusillo)
12 febbraio 2008 - Aula 713 - Seminario

ore 11:00-12:00 - G. Pistone (Politecnico Torino)

"STATISTICAL MODELS AS DIFFERENTIABLE MANIFOLDS AND ALGEBRAIC VARIETIES"

Abstract: The association of algebraic varieties and differentiable manifolds to statistical models is not a contingent fact. The case for such an association can show some evidence.

1. The algebraic and the geometric description coincide in many cases when the state space is finite. In such a case many theoretical ideas, such as model invariants or sufficiency can by computable in a symbolic way.

2. The algebraic geometry presentation has special features, typically related with the notion of algebraic degree, considered as an index of the complexity of the model.

3. The study of tangent and other vector bundles that arose in the differential geometry picture has a special interest in the algebraic case.

4. Approximation of continuous state models with discrete state models could lead to interesting connection of the algebra and the geometry. This is an area where few rigorous results are known.
5 febbraio 2008 - Aula 716 - Seminario di Geoemtria e Fisica (Mencattini)

ore 14:30 - G. Monti Bragadin

"TEORIA CLASSICA DELLE FORME AUTOMORFE: UN'INTRODUZIONE"

Abstract: Riepilogo essenziale su superficie di Riemann e gruppi fuchsiani
Costruzione delle serie di Poincare' come introduzione alla definizione di funzioni e forme automorfe
Corrispondenza tra k-forme automorfe e differenziali di peso k sulla corrispondente superficie di Riemann; divisori; teorema di Riemann-Roch
Spazio di Hilbert delle forme cuspidali; dimensione degli spazi vettoriali delle forme regolari e delle forme cuspidali
Esempi vari
Cenni a possibili generalizzazioni
28 gennaio 2008 - Aula 713 - Seminario di Teoria dei Giochi (Pusillo)
22 gennaio 2008 - Aula 716 - Seminario di Geoemtria e Fisica (Mencattini)

ore 14:30 - Mattia Cafasso (SISSA Trieste)

"Determinanti di Toeplitz a blocchi e gerarchie di Gelfand-Dickey"

Abstract: In questo talk verra' discusso come rappresentare un'ampia classe di funzioni tau per le gerarchie di Gelfand-Dickey come determinanti di Toeplitz a blocchi. Il simbolo associato a questi determinanti individua il corrispondente punto nella grassmanniana di Segal-Wilson. Tale rappresentazione permette di utilizzare il teorema di Szego-Widom per scrivere tali funzioni tau come determinanti di operatori integrali legati a uno specifico problema di Riemann-Hilbert.
18 gennaio 2008 - Aula 713 - Seminario (Zolezzi)

ore 11:00-13:00 - Zolesio

15 gennaio 2008 - Aula 706 - Seminario di Geoemtria e Fisica (Mencattini)

ore 14:30 - G. Mauceri

"Moltiplicatori spettrali per Laplaciani generalizzati: una panoramica dal punto di vista dell'analisi geometrica"

Abstract:
13 dicembre 2007 - Aula 508 - Seminario (Pusillo)

ore 17:00 - S. Giulini e M. Malagugini (Dipartimento di Scienze per l'Architettura, Universita di Genova)

13 dicembre 2007 - Aula 714 - Seminario di Statistica

ore 11:00 - Prof. G. Pistone (Polit. Torino)

"MODELLI ESPONENZIALI ESTESI II"

Abstract:
11 dicembre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - P. SINGLA

"Rigidity of Linear Strands and Generic Initial Ideal"

Abstract: Let $K$ be a field, $S$ a polynomial ring and $E$ an exterior algebra over $K$, both in a finite set of variables. We study rigidity properties of the graded Betti numbers of graded ideals in $S$ and $E$ when passing to their generic initial ideals. First, we prove that if the graded Betti numbers for some $i>1$ and $k \geq 0$,
$\beta_{ii+k}^S(S/I)=\beta_{ii+k}^S\big(S/\Gin(I)\big)$ then
$\beta_{qq+k}^S(S/I)=\beta_{qq+k}^S\big(S/\Gin(I)\big)$ for all $q \geq
i$,
where $I\subset S$ is a graded ideal.
Second, we show that if for some $i>1$ and $k \geq 0$,
$\beta_{ii+k}^E(E/I)= \beta_{ii+k}^E\big(E/\Gin(I)\big)$ then
$\beta_{qq+k}^E(E/I)= \beta_{qq+k}^E\big(E/\Gin(I)\big)$ for all $q \geq
1$, where $I\subset E$ is a graded ideal.
In addition, it will be shown that the graded Betti numbers
$\beta_{ii+k}^R(R/I)= \beta_{ii+k}^R\big(R/\Gin(I)\big)$ for all $i \geq 1$
if and only if $I_{\langle k \rangle}$ and $I_{\langle k+1 \rangle}$ have
a linear resolution.
Here $I_{\langle d \rangle}$ is the ideal generated by all homogeneous
elements in $I$ of degree $d$, and $R$ can be either the polynomial ring or the exterior algebra
5 dicembre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - T. ROEMER

""

Abstract: We consider monoidal complexes and their associated algebras, called toric face rings.
The construction of this class of rings generalize the concepts of Stanley Reisner rings and affine monoid algebras.
We compute initial ideals of the presentation ideal of a toric face ring, and determine its graded Betti numbers.
Our results generalize well-known theorems of Hochster in combinatorial commutative algebra.
27 novembre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - E. Sernesi

"Curve di genere geometrico basso sulle superfici K3"

Abstract: Dopo aver passato in rassegna i risultati classici di Mukai e altri riguardanti i moduli delle curve nonsingolari sulle superfici K3, esporro' una loro parziale generalizzazione alle curve singolari, che e' oggetto di un lavoro in collaborazione con F. Flamini, A. Knutsen e G. Pacienza, e discutero' alcuni problemi aperti sulll'argomento.
22 novembre 2007 - Aula 215 - Seminario di Algebre di Lie (Venturi)
20 novembre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - C. Novelli

"Varieta` di Fano di dimensione cinque con struttura di fibrato proiettivo"

Abstract: Sia Y una varieta` liscia e sia E un fibrato vettoriale su Y.
Assumiamo che il fibrato proiettivo X=P_Y( E) sia una varieta' di Fano.
Nel corso del seminario daremo risultati generali sulle terne (X=P_Y(E), Y, E) e classificheremo il caso in cui X e` una varieta` di Fano di dimensione 5 ed indice r=2.
Questi risultati sono contenuti in un articolo in collaborazione con Gianluca Occhetta.
15 novembre 2007 - Aula 508 - Seminario

ore 17:00 - Jerzy Kaczorowski, A. Mickiewicz University, Poznan (Polonia)

"RIEMANN HYPOTHESIS:
THE GREATEST MYSTERY OF MATHEMATICS"

5 novembre 2007 - Centro Culturale Galliera - Seminario

ore 16:00 - Furio Honsell (Universita' di Trieste

"P versus NP"

Abstract:
5 novembre 2007 - Aula 713 - Seminario di Analisi Armonica (Astengo)

ore 16:00 - M. Cowling (UNSW, Sydney)

"A vector-valued version of Hardy's theorem and an uncertainty principle for operators"

Abstract:
30 ottobre 2007 - Aula 215 - Seminario di Analisi Fourier (Zizzi)
22 ottobre 2007 - Aula 713 - Seminario di Teoria dei Numeri (Perelli)
19 ottobre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - C. CILIBERTO

"Sulla dimensione delle varieta` delle secanti"

Abstract: In questa conferenza si estendono i noti risultati di F. Zak sulle tangenze, sulla lineare normalita' e sulla classificazione delle varieta' di Severi. Lavoro in collaborazione con Luca Chiantini.

ore 15:45 - S. DI ROCCO

"Come quantizzare proprieta' geometriche di una immersione torica"

Abstract: Le varieta' toriche, oltre ad essere un'importante classe di esempi in geometria algebrica, rappresentano un ponte, molto utile, tra problemi di natura discreta e la geometria algebrica complessa. Tali problemi sono alla base di svariate problematiche in statistica, calcolo di sistemi polinomiali, teoria dei codici e altre discipline. Per questo e' importante
e sempre piu' di interesse riuscire a quantizzare propieta' geometriche di una immersione torica.
Lo scopo di questo seminario e' di illustrare come certi invarianti proiettivi di una immersione torica, come il difetto duale o difetto osculante, siano caratterizzati da corrispondenti proprieta' combinatoriche di politopi convessi.
16 ottobre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - J. MURRE

"The Picard Motive revisited"

Abstract: Let X be a smooth, projective variety. Then it is possible to construct the so-called " Picard motive" of X [Mu,90] . This is a Chow motive, the construction of which depends by its very nature on certain choices. This motive has finite dimension in the sense of S. Kimura [Kim,05]. Using this we show that the Picard Motive of X is unique up to a natural isomorphism. Also we show that the Picard motive of X is isomorphic to the Picard motive of the Albanese variety of X (joint work with S. Kimura).

Ref.:
[Murre,1990] ,On the motive of an algebraic surface. J. Reine und angew. Math. 409, 1990, 190-204.
[Kimura,2005], Chow groups can be finite-dimensional, in some sense. Math. Ann. 331, 2005, 173 -201.
15 ottobre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - RANESTAD

"The algebraic degree in semidefinite programming"

Abstract: The algebraic degree in semidefinite programming is computed as the degree of the dual variety of symmetric matrices. In the talk I will explain the connection, and give a simple formula for the degree
11 ottobre 2007 - Aula 714 - Seminario di Fisica Matematica (Bartocci)
9 ottobre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - A. Lanteri (Milano)

"Luoghi inflessionali degli scroll"

Abstract: Nel seminario esporro` un risultato recente ottenuto con Raquel Mallavibarrena
e Ragni Piene. Sia X uno scroll n-dimensionale su una curva liscia C, immerso
in uno spazio proiettivo, e sia L il suo fibrato iperpiano. I luoghi inflessionali di
X sono costituiti dai punti in cui le valutazioni dei getti delle sezioni di L calano
di rango. La speciale geometria di X comporta che certi fasci collegati ai fibrati
in getti di L siano localmente liberi. Ne risulta che i luoghi inflessionali di X si
possono descrivere per mezzo di tali fasci e cio` conduce a delle formule
esplicite per le loro classi di coomologia.
In particolare, queste formule permettono di mostrare che gli scroll razionali
normali bilanciati sono i soli scroll privi di flessi contenuti in uno spazio proiettivo
con dimensione in un range appropriato. Questo estende risultati stabiliti da
Shifrin e da Piene-Tai negli anni 80 per scroll 2-dimensionali.
Nel seminario verranno anche discussi alcuni risultati che ad essi si ricollegano
2 ottobre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - A. Conca

"Ideali contratti e Groebner fan della curva razionale normale"

Abstract: Lo studio degli ideali contratti da estensioni quadratiche in un anello regolare di dimensione 2 ha una lunga tradizione. Zariski introdusse questo concetto come strumento nello studio degli ideali integralmente chiusi e loro fattorizzazioni in prodotti. Il problema che discutero' riguarda l'anello graduato associato ad un ideale contratto e la sua eventuale Cohen-Macaulicita'. Il problema e', sorprendentemente, legato allo studio del Groebner fan dell'ideale della curva razionale normale di P^d nella sua rappresentazione torica (lavoro in collaborazione con E. De Negri e M.E. Rossi.)
27 settembre 2007 - Aula 713 - Seminario di Fisica Matematica (Bartocci)
24 settembre 2007 - Aula 713 - Seminario di Teoria dei Giochi (Pusillo)
20 settembre 2007 - Aula 714 - Seminario di Fisica Matematica (Bartocci)
14 settembre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - K. Watanabe

"Calculation of cohomology groups of certain blown-up space by Segre Product"

Abstract: This is a joint work with K. Kurano, A. Singh and E. Sato.

We want to find a pair $(X,L)$ of smooth projective variety $X$ and an ample line bundle $L$ with the property;

(1) $R=R(X,L)=\oplus_{n\ge 0} H^0(X,L^n $ is generated by degree 1,\par
(2) $H^1(X,O_X)=0$ and $H^1(X,L)\ne 0$.

Such space is obtained by blowing up $0$ dimensional subscheme (which is a complete intersection in $Y$) of a smooth hypersurface $Y$.

Ring theoretically, this problem reduces to compute local cohomology groups of certain diagonal subalgebra of a Rees algebra of a graded ideal $I\subset S$, which is generated by homogeneous regular sequence ($S$ is the coordinate ring of $Y$ above).

The theme of this talk is to compute the local cohomology groups explicitly using Segre product of graded modules.

ore 16:00 - Ngo Viet Trung

"Rees algebra and Integer Linear Programming"

Abstract: Every simplicial complex is given by the vertex-facet incidence matrix.
The talk will discuss properties of the Rees algebra of the facet ideal that can be described by well-known min-max equations defined by this matrix in Integer Linear Programming.
This relationship may have interesting applications in combinatorics and commutative algebra.
11 settembre 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:30 - M. Marietti

"Gruppi di Coxeter e accoppiamenti speciali"

Abstract: Gli accoppiamenti speciali hanno un ruolo fondamentale nella dimostrazione (ottenuta insieme a Brenti e Caselli) della congettura di Lusztig sull'invarianza combinatorica dei polinomi di Kazhdan-Lusztig per intervalli inferiori. In questo seminario vediamo come, grazie al concetto di accoppiamento speciale, possiamo definire degli insiemi parzialmente ordinati che generalizzano i gruppi di Coxeter e aiutano a comprenderne le proprieta` combinatoriche. L'ultima parte del seminario verra' dedicata ad alcuni problemi aperti.
20 luglio 2007 - Aula 705 - Seminario di Analisi Armonica (De Mari)

ore 15:00 - Prof. Labate (North Carolina State Univ.)

"Optimally sparse representations using shearlets"

Abstract: During the last 20 years, multiscale methods and wavelets have revolutionized signal processing, and stimulated an impressived amount of research in harmonic analysis. The major reason of this success is that wavelets are optimally efficient in dealing with point singularities of functions and signals.
Unfortunately, traditional multiscale methods are not equally efficient to represent multidimensional functions, where distributed discontinuities are usually present or even dominant. In this talk, we review some of the basic ideas emerged in recent years to address this problem, and present the Shearlets, a new multiscale directional representation which is optimally sparse for 2-dimensional functions with discontinuities along curves. Several applications of this approach to problems from analysis and image processing will be described.
29 giugno 2007 - Aula 714 - Seminario di dottorandi (Tacchella)
29 giugno 2007 - Aula 713 - Seminario di Teoria dei Giochi (Pusillo)
27 giugno 2007 - Aula 714 - Seminario di dottorandi (Tacchella)
25 giugno 2007 - Aula 714 - Seminario di dottorandi (Tacchella)
21 giugno 2007 - Aula 713 - Seminario di Analisi Numerica (Piana)
21 giugno 2007 - Aula 716 - Seminario di Seminario dottorandi

ore 11:00 - 13:00 - Tacchella

20 giugno 2007 - Aula 715 - Seminario di dottorandi (Tacchella)

ore 11:00 - Tacchella

20 giugno 2007 - Aula 713 - Seminario di Teoria delle Categorie (Pagnan)

ore 10:00 - Pagnan

12 giugno 2007 - Aula 713 - Seminario di Algebra Geometria

ore 15:00 - E. Arrondo

"Fibrati senza coomologia intermedia"

Abstract: Da quando Horrocks ha caratterizzato le somme di fibrati lineari di P^n come i fibrati che non hanno coomologia intermedia,
si conoscono diverse generalizzazioni di questo teorema a differenti spazi. Dopo una breve storia di questi risultati, spiegheremo
come usare certi metodi dello spazio proiettivo per ritrovare la caratterizzazione dei fibrati senza coomologia intermedia sulla grassmanniana
di rette di P^3. Finalmente, indicheremo come con questi metodi stiamo provando a classificare i fibrati di rango piccolo senza coomologia
intermedia sulla grassmanniana di rette di P^4.
8 giugno 2007 - Aula 713 - Seminario (Perelli)

ore 14:00-15:30 - prof. Diaconu

7 giugno 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
7 giugno 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - Muselli, Villa

"Invarianza e raggiungibilita'"

31 maggio 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)
24 maggio 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - Muselli, Villa

"Invarianza e raggiungibilita'"

24 maggio 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)

Pagina web

22 maggio 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - A. Knutsen

"Su una congettura di Harris e Mumford"

Abstract: In connessione col loro lavoro sugli spazi dei moduli di curve negli anni 80, Harris e Mumford congetturarono che la gonalita' delle curve liscie in un sistema lineare completo su una supeficie K3 e' costante. Poco dopo Donagi e Morrison trovarono un controesempio semplice (con un sistema lineare la cui curva generale isomorfa ad una sestica piana, quindi di gonalita' 5, e contenente una famiglia di codimensione uno di curve tetragonali).
In questo seminario dimostriamo che il controesempio di Donagi-Morrison e' in effetti l'unico tale controesempio. Questo risultato fu dimostrato da Ciliberto e Pareschi sotto l'ipotesi aggiuntiva che il sistema lineare sia ampio e la nostra dimostrazione e' un estensione di quella di Ciliberto-Pareschi.
Come conseguenza dimostriamo anche che le cosiddette CURVE ECCEZIONALI su una K3 (le curve il cui indice di Clifford non e' calcolato da un pencil) soddisfano la congettura di Eisenbud-Lange-Martens-Schreyer e le possiamo anche esplicitamente descrivere.
18 maggio 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
17 maggio 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - Muselli, Villa

"Invarianza e raggiungibilita'"

15 maggio 2007 - Aula 716 - Seminario di Teoria dei Numeri (Perelli)

ore 16:00 - prof. Srinivas

15 maggio 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 14:30 - A. Languasco

"Sulla somma di due primi e k potenze di due"

ore 15:45 - W. Bruns

"Covering properties of normal affine monoids"

11 maggio 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
10 maggio 2007 - Aula 508 - Seminario

ore 17:00 - prof. Jeff Weeks

"La forma dello spazio"

10 maggio 2007 - Aula 705 - Seminario di Analisi (Zolezzi)

ore 14:30 - A. Ioffe, Technion (Haifa)

"A Non-Smooth Sard Theorem"

Abstract: Sard (or Morse-Sard) theorem is among the very central (and technically difficult) results of analysis playing an important part in differential topology, dynamical systems and singularity theory. It says that the set of critical values of a sufficiently smooth mapping between finite dimensional spaces has Lebesgue measure zero. It might have important applications also in optimization theory (especially in stability and sensitivity analysis). This have not happened, however, as the strong smoothness requirements of the sard theorem are known to be sharp.

In the talk we shall describe a class of nonsmooth (and even set-valued mappings for which an extension of the Sard theorem appears to be possible. The class is surprisingly broad (many mappings which typically appear in practical situations are expected to belong to it) and its elements have remarkable structural and analytic properties. The very concept of a critical value of a set-valued mapping is derived as a negation of metric regularity, a property well studied in variational analysis, and is perfectly compatible with the classical concept in the smooth situations.

Some applications, mainly associated with optimization will also be discussed.
10 maggio 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - Zolezzi

""

9 maggio 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)
8 maggio 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:00 - A. Alzati

"Criteri numerici di molta ampiezza per fibrati di rango 2 su superfici rigate"

Abstract: La ricerca di criteri numerici sufficienti per la molta ampiezza di divisori e' un problema classico per la Geometria Algebrica. Il probema ovviamente risulta piu' abbordabile per varieta' X delle quali e' noto il gruppo di Picard e questo ha pochi generatori.
Per esempio quando X e' il proiettivizzato di un fibrato E di rango 2 su una superficie rigata razionale. Anche limitandosi a questo ambito ristretto, una soluzione del suddetto problema potrebbe condurre alla costruzione di numerose 3-varieta' di grado basso la cui esistenza e' per ora in dubbio. Nel presente seminario, dopo aver richiamato alcune classiche idee in merito, si presentera' una nuova tecnica che fa perno sul comportamento dei divisori da esaminare quando essi siano ristretti ad elementi riducibili di un'altro sistema lineare opportunamente scelto. Si dimostrera' che tale tecnica conduce a numerosi risultati sotto alcune ipotesi su E, ipotesi che in futuro si conta di ridurre o di ricondurre anch'esse al soddisfacimento di condizioni numeriche.
4 maggio 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
3 maggio 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - T. Zolezzi

""

27 aprile 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
26 aprile 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)

Pagina web

20 aprile 2007 - Aula 713 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
19 aprile 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - T. Zolezzi

"Inclusioni differenziali e stabilita'"

13 aprile 2007 - Aula 713 - Seminario di Algebra Geometria (Beltrametti)

ore 15:30 - A. Beauville (Nice)

"Holomorphic symplectic geometry"

Abstract: The basic definitions of symplectic geometry (symplectic form, contact structure, Poisson bracket...) make perfect sense in the holomorphic set-up. It turns out that projective manifolds endowed with these structures have a rich geometry, which gives rise to interesting (but difficult) questions in algebraic geometry. I will discuss:
- (holomorphic) symplectic manifolds, also called hyperkahler;
- projective Poisson manifolds, with an intriguing conjecture of Bondal;
- projective contact manifolds.
13 aprile 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
12 aprile 2007 - Aula 508 - Seminario (D. Arezzo)

ore 17:00 - A. Beauville (Univ. Nice)

"La congettura di Hodge"

12 aprile 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - L. Levaggi

"Inclusioni differenziali e controllo"

12 aprile 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)

Pagina web

6 aprile 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
5 aprile 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)
4 aprile 2007 - Aula 713 - Seminario di Fisica Matematica (Brolpasino)
30 marzo 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)

ore 14:00-16:30 - Filippo De Mari

29 marzo 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)

Pagina web

27 marzo 2007 - Aula 508 - Seminario di Fisica Matematica
23 marzo 2007 - Aula 713 - Seminario di Fisica Matematica (Brolpasino)
22 marzo 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - E. Punta

"Algoritmi di second'ordine"

15 marzo 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - E. Punta (ISSIA - CNR Genova)

"Sistemi di controllo a struttura variabile"

15 marzo 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)

Pagina web

13 marzo 2007 - Aula 713 - Seminario di Seminario Algebra-Geometria (Beltrametti)

ore 15:00 - G. PARESCHI (Roma Tor Vergata)

"Annullamento generico della coomologia e trasformate di Fourier-Mukai.

"

Abstract: I fenomeni di annullamento generico di gruppi di (iper)coomologia di
(complessi di) fasci coerenti, che variano in un dato spazio di moduli, sono ubiqui e
spesso molto rilevanti nello studio delle varieta' proiettive. Il contesto naturale per studiare
quando e come si ha l'annullamento generico sono le trasformate di Fourier-Mukai. In questo
ambito si ottengono alcuni risultati del tutto generali che si possono applicare in varie direzioni,
tra cui: criteri di annullamento generico di tipo Kodaira-Kawamata-Viehweg, metodi per lo studio e
la classificazione di varieta' irregolari, problema di Schottky, criteri di ampiezza per fasci su
varieta' abeliane, spazi di moduli di fibrati vettoriali. Si tratta di ricerche svolte in collaborazione
con Mihnea Popa.
9 marzo 2007 - Aula 713 - Seminario di Analisi Armonica (Astengo)

ore 15:00 - Peter Sjogren (Goteborg)

"Operatori di Riesz per le espansioni di Jacobi"

8 marzo 2007 - Aula 508 - Seminario (D. Arezzo)

ore 17:00 - Prof. Carlo Petronio (Universita' di Pisa)

"La congettura di Poincare'"

8 marzo 2007 - Aula 716 - Seminario di Controllo dei Sistemi (Zolezzi)

ore 11:00 - G. Bartolini (Cagliari)

"sistemi di controllo a struttura variabile"

1 marzo 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)

Pagina web

22 febbraio 2007 - Aula 508 - Colloquium Mathematicum

ore 16:00 - prof. U. Bruzzo (SISSA - Trieste)

21 febbraio 2007 - Aula 713 - Seminario di Seminario Dottorato (Brolpasino)
20 febbraio 2007 - aula 715 - Seminario di Seminario Dottorato (Brolpasino)
16 febbraio 2007 - Aula 713 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
15 febbraio 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)

Pagina web

14 febbraio 2007 - Aula 713 - Seminario di Seminario Dottorato (Brolpasino)
13 febbraio 2007 - aula 715 - Seminario di Seminario Dottorato (Brolpasino)
2 febbraio 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
1 febbraio 2007 - Aula 713 - Seminario di Seminario Giovani (Scorza)

Pagina web

31 gennaio 2007 - Aula 713 - Seminario di Seminario Dottorato (Brolpasino)
26 gennaio 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
25 gennaio 2007 - Aula 716 - Seminario di Seminario Giovani (Scorza)

Pagina web

24 gennaio 2007 - Aula 713 - Seminario di Seminario Algebra-Geometria (Beltrametti)

ore 15:00 - C. Ciliberto (Roma II)

""

Abstract:
19 gennaio 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
12 gennaio 2007 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
11 gennaio 2007 - Aula 217 - Seminario di Seminario Giovani (Scorza)

Pagina web

ore 14:30 - Giovanni Casella

22 dicembre 2006 - Aula 216 (DISI) - Seminario di Combinatorics of Coxeter Groups (Sbarra)
21 dicembre 2006 - Aula 217 - Seminario di Seminario Giovani (Scorza)

Pagina web

ore 14:30 - Massimo Brignone

15 dicembre 2006 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
14 dicembre 2006 - Aula 508 - Colloquium Mathematicum (Pusillo)

ore 17:00 - prof. Hisao Fujita Yashima (Univ. Torino)

"Scorrimento accidentato delle equazioni di Navier-Stokes "

12 dicembre 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria (Conca)

ore 14:30 - V. Brinzanescu (Bucarest)

"Beilinson type spectral sequences on scrolls
"

Abstract: One constructs Beilinson type sequences on scrolls using resolutions
of diagonals inside the usual product (not the fibred product as
Orlov did). In the case of Hirzebruch surfaces, one recovers the
spectral sequence of Buchdahl. As an application one ontains that
the bundle of relative differentials on a 3-dimensional rational
scroll is completely determined by the cohomology of suitable twists.

ore 15:45 - B. Berceanu (Bucarest)

"Iterated Tschirnhausen operators
"

Abstract: In order to understand $ Aut(\bbC [X,Y]) $, we study an associated
system of $ 2n-1 $ differential equations. We prove that this system
is completely integrable and we express the solutions as an affine
algebraic variety in $ \bbC ^{2n-1}\times \bbC [X]^{n-1} $. The
irreducible componenets of this variety are related to $\log-
$partitions of the number $ n $ (for instance, if $ n=6 $, $ \log 6
$, $ \log 2+\log3 $, $ \log 3+\log 2 $).
7 dicembre 2006 - aula 714 - Seminario (Piana)
7 dicembre 2006 - Aula 217 - Seminario di Seminario Giovani (Scorza)

Pagina web

ore 14:30 - Stefano Moretti

5 dicembre 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria (Conca)

ore 15:00 - F. Brenti (Roma2)

"La formula piu' semplice per i polinomi di Kazhdan-Lusztig
"

Abstract: Nel 1979 Kazhdan e Lusztig introdussero una famiglia di
polinomi, indicizzati da coppie di elementi di un qualsiasi
gruppo di Coxeter, che sono ora noti come polinomi di Kazhdan-
Lusztig. Questi polinomi sono definiti tramite una complicata
ricorsione, e giocano un ruolo importante in diverse branche
della matematica, incluso teoria delle rappresentazioni,
geometria delle varieta' di Schubert, e polinomi di Macdonald.

Lo scopo di questo seminario e' di presentare una formula chiusa
(cioe', non ricorsiva) per il loro calcolo, e di dimostrare, in un senso
ben preciso, che non esiste una formula piu' semplice per il calcolo
di questi polinomi che vale per tutte le coppie di elementi di tutti i
gruppi di Coxeter. La dimostrazione usa una funzione quasi-simmetrica,
associata ad ogni coppia di elementi di un qualsiasi gruppo di Coxeter,
che e' introdotta qui per la prima volta. Questo lavoro e' in
collaborazione con L. Billera.
1 dicembre 2006 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
30 novembre 2006 - Aula 508 - Colloquium Mathematicum (Pusillo)

ore 17:00 - Prof. M. Bertolini (Univ. Milano)

"LA CONGETTURA DI BIRCH E SWINNERTON-DYER"

30 novembre 2006 - Aula 217 - Seminario di Seminario Giovani (Scorza)

Pagina web

ore 14:30 - Martina Kubitzke

27 novembre 2006 - aula 714 - Seminario di Statistica Matematica (Rogantin)

ore 14:30-16:00 - Prof. Pistone

"Modelli esponenziali e semigruppi secondo S. Lauritzen (Oxford UK)"

24 novembre 2006 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
17 novembre 2006 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
14 novembre 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria

ore 15:00 - Prof. P. Ionescu

"Kleiman-Mori Cones of Hyperplane Sections of Projective Manifolds
"

Abstract: Comparing a projective manifold X with one of its hyperplane sections H is a classical theme of Projective Geometry. One of the basic "modern" techniques is due to Lefschetz and concerns the way in which H reflects the topology of X. Vanishing results of Kodaira type are closely related to this topological approach. In the mid 70's, A.J. Sommese discovered several interesting results in this area, by combining Lefschetz theory with vanishing techniques. The powerful methods of Mori Theory made possible several refinements, based on comparing the Kleiman-Mori Cones of X and H, respectively. I will survey recent progress on the subject, as well as some open questions and conjectures. Joint work with Mauro C. Beltrametti.
3 novembre 2006 - Aula 713 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
31 ottobre 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria (Conca)

ore 14:00 - T. Roemer (Osnabrueck)

"On algebras associated to finite posets in combinatorial commutative
algebra"

Abstract: Some interesting algebras in combinatorial commutative
algebra like Stanley-Reisner rings
can be seen as the rings of global sections of sheafs on the
Alexandrov space of a finite poset.
We present some recent results on these algebras which are motivated
by this point of view.
Special attention is given to the case of toric face rings which are
rings associated to (the face posets of) rational pointed fans.
27 ottobre 2006 - Aula 705 - Seminario di Combinatorics of Coxeter Groups (Sbarra)
24 ottobre 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria

ore 15:00 - E. Carlini (Torino)

"Existence result for rational normal curves (joint with M.V. Catalisano)
"

Abstract: In this paper we study existence and uniqueness of rational normal curves in $\PP^n$ passing through $p$ points and intersecting $l$ codimension two linear spaces in $n-1$ points each. If $p+l=n+3$ and the points and the linear spaces are generic, one expects the curve to exists, but this is not always the case. Our main result precisely describes in which cases the curve exists and in which it does not exist.
20 - 21 ottobre 2006 - Aula 706 - Seminario di Workshop "progetto INDAM" (Beltrametti)

Pagina web

20 - 21 ottobre 2006 - Aula 215 - Seminario di Workshop "Progetto INdAM" (Beltrametti)

11:00 - 11:30 e 16:00 - 16:30 coffee break

ore 10:00-12:30 - A. Lopez (Univ. Roma III)

""

Abstract:

ore 11:30-12:30 - C. Casagrande (Univ. Pisa)

""

Abstract:

ore 15:00-16:00 - M. Mella (Univ. Ferrara)

"Ipersuperfici cubiche"

Abstract:

ore 16:30-17:30 - F. Zucconi (Univ. Udine)

"Graded rings of rank 2 Sarkisov links"

Abstract: E' calcolata esplicitamente una classe di links di Sarkisov ottenuti a partire da un 3-fold di Fano immerso in una Grassmanniana pesata. Tali metodi espliciti sono ottenuti tramite anelli graduati associati a una variazione di GIT-quozienti.
17 ottobre 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria

ore 15:00 - G. Ottaviani (Univ. Firenze)

"Varieta' delle secanti e tensori"

Abstract:
4 ottobre 2006 - Aula 713 - Seminario di Working Seminar - I incontro (Sbarra)
3 ottobre 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria

ore 14:30 - S. Hosten (San Francisco)

"Growth Series of Cyclotomic Lattices and Cyclotomic Polytopes
"

Abstract: Cyclotomic lattices are abelian groups generated by the set M(m) of a
primitive m-th root of unity and its powers. The growth series of this
lattice is the generating function for the word length of its elements
with respect to M(m). We settle a few conjectures about the numerator
polynomial of the growth series. In particular, we show that the
coefficients of this polynomial are nonnegative, unimodal, and
palindromic when m is divisible by at most two odd primes. These
results are obtained by studying the cyclotomic polytope C_m and the
h-polynomial of the associated toric ring. The talk is based on joint
work with Matthias Beck.

ore 15:45 - L. Badescu (Dima)

"Un teorema di tipo Barth-Larsen per le sottovarieta' di P^m\times P^n.
"

Abstract: Se X e' una sotovarieta' liscia di P^m\times P^n, denotiamo
con \alpha:Pic(P^m\times P^n)\to Pic(X) la mappa di restrizione tra i
gruppi di Picard. Presento un teorema che afferma che, sotto certe
ipotesi riguardanti la codimensione di X, la mappa \alpha e' iniettiva e
il suo conucleo e' senza torsione, e che la sottovarieta' X e
semplicemente
connesa. Si danno anche coondizioni sufficienti affinche' \alpha sia un
isomorfismo. Il risultato migliora nel caso di P^m\times P^n un noto
risultato generale di Sommese (che riguarda le sottovarieta' di
codimensione
"piccola" di uno spazio omogeneo razionale). La presentazione e'
basata su
un lavoro in collaborazione con la mia dottoranda Flavia Repetto.
26 settembre 2006 - Aula 713 - Seminario di Algebra-Geometria

ore 15:00 - C. Krattenthaler (Vienna)

"Generalized non-crossing partitions and the generalized cluster complex
"

Abstract: I shall present, in a motivated fashion, the generalized non-crossing
partitions of Drew Armstrong, combinatorial objects that are
associated to finite reflection groups. They are fascinating in many
ways. In particular, they have extremely interesting enumerative
properties, some of which I will mention. The main result of the talk
will be a surprising relation between the M\"obius function of the
poset of generalized non-crossing partitions and certain face numbers
of the generalized cluster complex of Fomin and Reading.
21 settembre 2006 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)
20 settembre 2006 - Aula 713 - Seminario di Logica (Pagnan)
19 settembre 2006 - aula 715 - Seminario di Teoria dei numeri (Perelli)

ore 14:30-15:30 - Prof. Coppola

19 settembre 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria

ore 15:00 - B. Ichim (Osnabrueck)

"On toric face rings"

Abstract: Following a construction of Stanley we consider toric face rings
associated to rational pointed fans. This class of rings is a common
generalization of the concepts of Stanley--Reisner and affine monoid
algebras. The main goal of this talk is to unify parts of the
theories of Stanley--Reisner and affine monoid algebras. We study
the Cohen--Macaulay property, the local cohomology, the canonical
module and the Gorenstein property of a toric face ring."
18 luglio 2006 - Aula 713 - Seminario di Processi Stocastici (De Vito)
10 luglio 2006 - Aula 704 - Seminario di Geometria e Fisica (Bartocci)
10 luglio 2006 - Aula 706 - Seminario di Analisi Armonica (De Mari)

ore 15:00 - Prof. Demetrio Labate (University of North Carolina)

"Sparse representations of multidimensional functions using shearlets"

23 giugno 2006 - Aula 713 - Seminario di Didattica (Morselli)
13 giugno 2006 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 15:00 - B.Harbourne (Lincoln)

"Classifying finite sets of points in P2"

Abstract: One approach to classifying finite point sets in the plane is the matroid approach, in which all that counts is collinearity.
I will discuss work joint with A.V. Geramita and J. Migliore which in certain cases extends this to a classification in which higher degree curves count. We obtain an explicit classification of all subsets of up to 8 points, and of all subsets of any finite number of points on a conic. These classifications allow us to explicitly determine which Hilbert functions occur for fat point subschemes supported at the points, and, in the case of points on a conic, based on work of M. V. Catalisano, also the graded Betti numbers.
9 giugno 2006 - aula 714 - Seminario (Perelli)

ore 14:30-15:30 - prof. Bruedern

6 giugno 2006 - Aula 713 - Seminario

ore 15:00 - Francisco Javier Gallego (Madrid)

"(da stabilirsi)"

1 giugno 2006 - aula 714 - Seminario (Perelli)

ore 11:00-12:00 - prof. Pintz

1 giugno 2006 - aula 714 - Seminario (Perelli)

ore 14:30-15:30 - prof. Pintz

31 maggio 2006 - Aula 508 - Colloquium Mathematicum (Pusillo)

ore 17:00 - J.Pintz (Hungarian Academy of Science-Budapest)

"LANDAU'S PROBLEMS ON PRIMES"

Abstract: At the 1912 Cambridge International Congress, Landau listed four basic problems about primes. These problems were characterised in his speech as "unattackable at the present state of science". The problems were the following.
(1) The Goldbach conjecture, that every even number exceeding 2 can be written as the sum of two primes.
(2) The Twin Prime Conjecture, the existence of infinitely many twin primes.
(3) Does there exist always at least one prime between neighbouring squares ?
(4) Are there infinetely many primes p such that p-1 is a square ?
All these problems are still open. In the lecture a survey will be given about partial results on problems (1)-(3), with special emphasis on the recent results of D. Goldston, C. Yildirim and the speaker on small gaps between primes.
31 maggio 2006 - Aula 716 - Seminario (Perelli)

ore 14:30-15:30 - prof. Pintz

30 maggio 2006 - Aula 706 - Seminario (Brianzi)

ore 15:00 - Christine De Mol - Departement de Mathematique, Universite' Libre de Bruxelles

"SPARSE SOLUTION TO INVERSE PROBLEMS"

Abstract: We show that sparsity constraints are useful for solving special kinds of linear inverse problems and that regularized solutions can be derived by means of a weighted ll-penalty on the coefficients of the expansion of the solution on a prescribed orthonormal basis (such as e.g. a wavelet basis). Contrary to the usual quadratic penalties used e.g. in Tikhonov's regularization, this type of penalty favours the sparsity of this expansion. We describe the properties of an iterative algorithm that can be used to compute such sparse solutions and that amounts to a Landweber iteration with soft-thresholding applied at each iteration step.
We discuss several recent extensions of these results as well as practical applications.
30 maggio 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria

ore 15:00 - R. Buchweitz (Univ. Toronto)

23 maggio 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria

ore 14:30 - T. De Fernex (Utah)

"Curve con autointersezione negativa su scoppiamenti generici del
piano proiettivo.
"

Abstract: La congettura e` che ogni curva con autointersezione negativa su
scoppiamenti "molto generici" del piano proiettivo e` liscia e
razionale, e l'autointersezione e` -1. Tale curva si chiama (-1)-
curva. In questo seminario daro` una panoramica generale sul
problema, spiegando il legame con the congetture di Nagata e di Segre-
Harbourne-Gimigliano-Hirschowitz. Poi mostrero` che la congettura e`
soddisfatta da tutte le curve la cui immagine sul piano ha un punto
doppio tra i punti base dello scoppiamento.

ore 15:45 -

"
A SURVEY ON RECENT RESULTS ON FORMS OF HIGHER DEGREE
"

Abstract:
19 maggio 2006 - Aula 508 - Seminario di Seminario Algebra -Geometria (Conca)

ore 14:00-16:00 - Prof. Hartshorne

19 maggio 2006 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - Prof. Hartshorne

" On the history of imaginary numbers
"

Abstract: ABSTRACT: At first, square roots of negative numbers were simply
considered impossible. But when Rafael Bombelli in the mid-16th century
discovered that he could obtain real solutions of certain cubic equations by
calculating with these impossible quantities, imaginary numbers started
being used, and gave many important results even while remaining
illogical. It was only at the beginning of the 19th century that the
theory could be justified rigorously, thanks to the work of Wessel,
Argand, Gauss, Cauchy and Hamilton.
18 maggio 2006 - aula 714 - Seminario di Geometria Algebrica (Geramita)

ore 14:00-16:00 - De Fernex

18 maggio 2006 - Aula 508 - Colloquium Mathematicum (Pusillo)

ore 16:00 - B. Falcidieno

"Forme digitali e mondo virtuale"

17 maggio 2006 - Aula 704 - Seminario di Seminario Giovani
16 maggio 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria (Conca)

ore 14:30 - E. Hyry (Helsinki University)

"Jumping numbers of a simple complete ideal in a two dimensional
regular local ring
"

Abstract: This is joint work with T. J\"arvilehto. We give a formula for the
jumping numbers in terms of the multiplicity sequence of the ideal.
Remarkably, the jumping numbers conversely determine the multiplicity
sequence. The set of jumping numbers turns out to divide into subsets
corresponding to the stars in the dual graph of the associated
minimal resolution. Our result applies also to jumping numbers of an
analytically irreducible plane curve. In particular, its
equisingularity class is determined by the jumping numbers.

ore 15:45 - G. Smith (Kingston University, Canada)

"Toric varieties as fine moduli
"

Abstract: We'll discuss how projective toric varieties can be realized as a
fine moduli space for stable representations of a quiver.
11 maggio 2006 - Aula 508 - Seminario (Pusillo)

ore 16:00 - Prof.ssa Anna Schomachen (Facolta' di Economia)

11 maggio 2006 - aula 714 - Seminario (Perelli)

ore 14:30-15:30 - Prof. Rogers

9 maggio 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria (Conca)

ore 14:30 - T. Shioda (Rikkyo)

"Classical Kummer Surfaces and Mordell-Weil Lattices
"

Abstract: We discuss the Kummer surface of a genus two Jacobian variety as an
elliptic surface with special type of singular fibres. We determine
the Mordell-Weil lattice, and the explicit generators (in the general
case) by using the height formula. Results can be stated in very
simple form in terms of the defining equation of genus two curve.

ore 15:45 - E. Arrondo (Madrid)

"Il gruppo di Picard delle sottovarieta' di codimensione piccola.
"

Abstract: Le sottovarieta' X di P^N tendono a essere piu' speciali quando la
loro dimensione n diventa piu' vicina ad N. Per esempio, una nota
congettura di Hartshorne afferma che, se 2N<3n, allora X deve essere
un'intersezione completa. Il risultato piu' importante in questo
senso e' un teorema di Barth-Larsen che dice che X eredita la
coomologia di P^n fino all'ordine 2n-N. In particolare, se N<=2n-2,
il gruppo di Picard di X e' generato dalla sezione iperpiana. In
questo seminario, racconteremo un metodo (sviluppato nella tesi di
dottorato di Jorge Caravantes) per ridimostrare quest'ultimo
risultato (modulo divisibilita' del gruppo di Picard). Spiegheremo
come questo metodo si puo' estendere ad altre varieta' ambiente, come
grassmanniane o prodotti di spazi proiettivi, migliorando fino al
range di Barth-Larsen risultati di Barth, Sommese e Van de Ven
sull'ereditabilita' del gruppo di Picard di sottovarieta'.
8 maggio 2006 - Sala Riunioni 427 - Seminario di Geometria delle Grassmanniane

ore 10:00-12:00 - E. Arrondo

4 maggio 2006 - Sala Riunioni 427 - Seminario di Geometria delle Grassmanniane (Geramita)

ore 9:00-11:00 - E.Arrondo

4 maggio 2006 - Aula 706 - Seminario di Algebra-Geometria "Speciale"

ore 14:30 - R. Lazarsfeld (Ann Arbor)

2 maggio 2006 - Aula 704 - Seminario di Seminario Algebra -Geometria

ore 15:00 - R. Lazarsfeld (Ann Arbor)

11 aprile 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria (Conca)

ore 15:00 - G. P. Pirola (Univ. Pavia)

"Sottocampi del campo delle funzioni razionali di una superficie
generica dello spazio proiettvo
"

Abstract: SUNTO: Sia X una superficie generica complessa di grado d dello
spazio proiettivo.I sottocampi del campo delle funzioni razionali di
X contenenti il campo base, sono in corrispondenza con mappe
razionali dominanti da X ad una varieta' Y. Si dimostra, per 4<d<11,
che l'unica applicazione razionale dominante da X ad Y, Y di tipo
generale, e' l'identita' . Questi studi si inquadrano nel tentativo
di dare versioni birazionali di risultati tipo Noether-Lefschetz.

ore 15:45 - R. Raghavan (Chennai University)

"On a certain ring of polynomial invariants.
"

Abstract: Abstract: To begin with, we will see what is meant by a ring of
invariants, and, more importantly, why in the first place their
study might be of interest. In the process we will introduce the
particular ring of invariants referred to in the title: namely the
one for the action of the special orthogonal group SO(V) on several
copies of a vector space V endowed with a non-degenerate symmetric
bilinear form. You can think of V as a usual Euclidean real vector
space and SO(V) as the group of linear automorphisms preserving inner
product and orientation. It is therefore natural to expect that
inner products and determinants in fact generate the ring of
invariants. The first fundamental theorem of invariant theory (in
the present case) says that this is indeed so. We will outline an
approach to the proof of this theorem over a field of arbitrary
characteristic. On the way we will also motivate our main theorem
that this ring of invariants is Cohen-Macaulay.
The work is joint with V. Lakshmibai, P. Sankaran, and P. Shukla.
10 aprile 2006 - Aula 706 - Seminario di Didattica (Morselli)
4 aprile 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria (Conca)

ore 15:00 - C. Ciliberto (Univ. Roma 2)

""

Abstract:

ore 15:45 - L. Gatto (Univ. Torino)

"Calcolo di Schubert su un'Algebra di Grassmann
"

Abstract:
28 marzo 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria (Conca)

ore 15:00 - M. Kreuzer (Univ. Dortmund)

"Computing Approximate Border Bases
"

Abstract: Abstract. After we have seen that border bases of zero-dimenisonal
polynomial ideals (in particular ideals of polynomials having
floaring-point coefficients) have important practical applications,
we study in this talk algorithms for computing them. First we examine
the border basis algorithm for exact arithmetic. Then we use the
singular value decomposition of a matrix of real numbers to adapt the
exact algorithm to the approximate setting. Finally, we discuss the
Improved (Approximate) Border Basis Algorithm and apply it to a
concrete example.

ore 15:45 - L. Robbiano (Dima)

"Pozzi petroliferi, ideali di punti e "border bases".
"

Abstract: Abstract: La ricerca di modelli polinomiali per la gestione di
giacimenti petroliferi ha recentemente portato alla ribalta problemi
di interpolazione approssimata. Lo strumento algebrico piu` naturale
e` quello rappresentato dagli ideali di punti. E la loro
rappresenatzione piu` naturale sembra essere quella ottenuta mediante
"border bases". Ma, a differenza di quanto si fa comunemente in
Algebra, i coefficienti dei nostri polinomi non sono necessariamente
esatti. Partendo da qui, faro` alcune considerazioni su problemi
matematici che nascono da questi studi.
23 marzo 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria "Speciale"

ore 14:30 - G. Rosenberger (Dortmund)

"Group properties I met in my life.
"

Abstract: Abstract: It will be a non-technical and entertaining introduction to
some current topics in combinatorial and geometric group theory.

ore 15:45 - Xinxian Zheng (Essen-Duisburg)

"Note on the multiplicity conjecture
"

Abstract:
22 marzo 2006 - Aula 706 - Seminario di Geometria e Fisica (Bartocci)

ore 14:30 - D. Brolpasino

"Costruzione ADHM"

22 marzo 2006 - Aula 713 - Seminario (Perelli)

ore 14:30-15:30 - Molteni

21 marzo 2006 - Aula 713 - Seminario di Seminario Algebra -Geometria (Conca)

ore 15:00 - J. Herzog (Essen-Duisburg)

"Symbolic powers of monomial ideals and vertex cover algebras

"

Abstract:

ore 15:45 - M. Cornalba (Univ. Pavia)

"Disuguaglianze di slope per superficie fibrate"

Abstract:
Sia X una superficie fibrata su una curva B, e sia g il genere della
fibra. Se la fibrazione e' relativamente minimale la classica
disuguaglianza di slope dice che il rapporto tra l'autointersezione
del fascio canonico relativo e il grado dell'immagine diretta di
questo stesso fascio e' limitata inferiormente da 4(g-1)/g. Questa
disuguaglianza e' ottimale, ma e' naturale ritenere che ponendo
limitazioni sul tipo di fibrazione che si considera si possano
ottenere disuguaglianze migliori. Discutero' il problema in alcuni
casi specifici, come ad esempio quello delle fibrazioni doppie e
quello delle fibrazioni non albanese, nei quali ci sono stati
progressi recenti.
16 marzo 2006 - Aula 508 - Colloquium Mathematicum (F. De Mari)

ore 17:00 - Giorgio Tommasini

"ANALISI ARMONICA NELLA REALIZZAZIONE
DI STRUMENTI MUSICALI VIRTUALI
Il caso dello Stradivari
"

Abstract:
14 marzo 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria

ore 15:00 - C. Pedrini (Dima)

"Il motivo di Chow di una superficie K3
"

Abstract: Sunto: Sia X una superficie K3 complessa, In virtu' di un risultato
di Deligne esiste una fibrazione proiettiva liscia su una curva C
tale che la fibra generica e' una superficie K3 , la fibra
corrispondente ad un punto chiuso P_0 e' X e la fibra corispondente
ad un punto chiuso P_1 e'una superficie K3 eccezionale X_1 ( cioe'
con rango del Pic massimo eguale a 20), Utilizzando tale risultato e
un teorema di Beuville-Voisin sul gruppo di Chow di una K3 si vede
come varia la parte trascendente del motivo di Chow per le superfici
della famiglia.
8 marzo 2006 - Aula 713 - Seminario di Geometria e Fisica
7 marzo 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria (Conca)

ore 15:00 - C. Turrini (Univ. Milano)

"Un'applicazione della geometria algebrica alla computer vision:
luoghi critici per la ricostruzione di scene dinamiche.
"

Abstract: Abstract: Si richiamano alcuni strumenti di geometria proiettiva
utilizzati nell'ambito della computer vision per problemi di
ricostruzione di scene da una o piu' immagini fotografiche. Si
generalizzano questi strumenti al caso di ricostruzioni di scene
dinamiche, seguendo l'approccio di A.Shashua e L.Wolf [On Projection
Matrices P^k to P^2, k=3,...6, and their Applications in Computer
Vision - International Journal of Computer Vision, 48(1), (2002),
53-67]. Si illustrano infine i primi risultati relativi ai luoghi
critici per tali ricostruzioni. In particolare, nel caso di una
vista, si dimostra che i luoghi critici per la calibrazione di una
camera in una scena dinamica corrispondono a varieta` cubiche di
codimensione due in P^k, che risultano essere sempre singolari per k>6.
28 febbraio 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria (Conca)

ore 15:00 - R. Pardini (Univ. Pisa)

"Il gruppo fondamentale delle superfici con K^2 "piccolo".
"

Abstract: Gli invarianti numerici di una superficie complessa minimale di tipo
generale soddisfano le disuguaglianze:
2\chi-6 <=K^2<=9\chi. Da tempo si e' compreso che, piu' il rapporto
K^2/\chi e' piccolo, piu' il gruppo fondamentale algebrico della
superficie e' semplice, come e' evidenziato da risultati per le
superfici con K^2<3\chi ottenuti negli anni '70-'80 da diversi autori
(Bombieri, Horikawa, Reid, Xiao).
In questo contesto si inquadra anche la disuguglianza di Severi, che
afferma che la mappa di Albanese di una superficie irregolare con
K^2<4\chi ha per immagine una curva.
Esporro' la dimostrazione di questa disuguaglianza, basata sulla
"slope inequality" (Xiao G., Cornalba Harris) per le superfici
fibrate su una curva. Mostrero' poi come i risultati gia' noti sul
gruppo fondamentale delle superfici con K^2<3\chi possano essere
riottenuti facilmente utilizzando la disuguaglianza di Severi e la
slope inequality.
Infine esporro' alcuni risultati recenti, ottenuti in collaborazione
con M. Mendes Lopes, sul gruppo fondamentale delle superfici con
K^2<=3\chi.

ore 15:45 - L. Buse

"Implicitizing rational parameterizations of surfaces using resultants and syzygies
"

Abstract: Given a parameterized (rational) surface, the implicitization problem
consists in the computation of its implicit equation. In this talk,
we will discuss two algebraic/geometric methods to solve the
implicitization problem in terms of matrices; most of the time the
implicit equation is obtained as the determinant of a certain
complex. As we will see, the main difficulty in this problem is the
presence of base points (that is to say when the parameterization is
a rational map) that we will "remove" by blowing-up the base locus
ideal. We will begin with a resultant-based method which has the
particularity to give a universal implicit equation for a certain
class of surfaces. Then, we will turn to a syzygy-based method that has been developped in collaboration with Marc Chardin and Jean-Pierre Jouanolou.
27 febbraio 2006 - Aula 508 - Seminario di Didattica (Boero)
22 febbraio 2006 - Aula 713 - Seminario di Geometria e Fisica

ore 14:30 - Brolpasino

21 febbraio 2006 - Aula 713 - Seminario di Seminario Algebra-Geometria (Conca)

ore 15:00 - J. Watanabe (Tokai)

"The central simple modules of Artinian Gorenstein algebras
"

16 febbraio 2006 - Aula 706 - Seminario di OpenWeek (Rogantin)

ore 15:00 - Dott. Vincenzo Fontana

"Metodi statistici per la salute dei cittadini"

15 febbraio 2006 - aula 715 - Seminario di Algebra Computazionale (Robbiano)
14 febbraio 2006 - Aula 706 - Seminario di OpenWeek (Rogantin)

ore 15:00 - prof. Alessandro Verri

"Computer che imparano a vedere guardando"

8 febbraio 2006 - Aula 706 - Seminario di OpenWeek (Rogantin)

ore 15:00 - Prof. Enrico Massa

"Geometria e Fisica: l'evoluzione del concetto di spazio da Euclide ad Einstein"

6 febbraio 2006 - Aula 706 - Seminario di OpenWeek

ore 15:00 - Dott. Mirko Innocenti

"Informatica da CSI"

18 gennaio 2006 - aula 714 - Seminario di Geometria e Fisica (Bartocci)
20 dicembre 2005 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)
15 dicembre 2005 - Aula 706 - Seminario di Teoria dei numeri (Perelli)

ore 15:30 - Prof. Zannier

6 dicembre 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

5 dicembre 2005 - Aula 704 - Seminario di Geometria (Beltrametti)

ore 16:30 - Ionescu-Beltrametti

""

29 novembre 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 15:00 - Andreas Knudsen (Univ. Oslo)

"Teoria di Brill-Noether di curve su una superficie d'Enriques ed il cono positivo della superficie.
"

Abstract:
28 novembre 2005 - aula 714 - Seminario di Seminario Constantinescu (Conca)
23 novembre 2005 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)
15 novembre 2005 - Aula 713 - Seminario di Algebra-Geometria

ore 15:00 - Frediani Paola (Univ. Pavia)

"Fibrati principali olomorfi in tori su tori
"

Abstract: In questo seminario presentiamo alcuni risultati ottenuti in
collaborazione con Fabrizio Catanese in cui studiamo le deformazioni in
grande dei fibrati principali olomorfi in tori su tori. Piu'
precisamente, consideriamo la mappa di Kodaira-Spencer della famiglia
completa di Appell-Humbert e dimostriamo che in questo modo otteniamo
una componente connessa dello spazio delle strutture complesse, nel
caso in cui la base abbia dimensione 2, la fibra dimensione 1 e sia
soddisfatta una condizione topologica. Questa descrizione e' molto
utile anche per lo studio delle possibili strutture reali su tali
fibrati. Diamo infatti un'altra dimostrazione del fatto che lo spazio
dei moduli delle superficie di Kodaira reali di un dato tipo topologico
e' connesso e a mostriamo che questo non accade per fibrati principali
olomorfi reali in tori su tori di dimensione 3.
10 novembre 2005 - Aula 508 - Seminario (Pusillo)

ore 17:00 - prof. Dorian Goldfeld, Columbia University

"On Gauss' class number problem"

Abstract: Gauss conjectured that his tables of class numbers published in the
Disquisitiones Arithmeticae in 1801 were complete and that there should be
an effective algorithm to determine all imaginary quadratic fields with a
given class number. While visiting Pisa, 1974-1975, I showed that Gauss'
conjecture could be reduced to a special case of the Birch-Swinnerton-Dyer
conjecture
on elliptic curves. This conjecture was solved by Gross-Zagier in 1984 and
then the three of us won the Cole Prize in number theory shortly after that
for the solution of Gauss' conjecture on class numbers. This talk will
outline the history of the problem and some ideas of the solution.
9 novembre 2005 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)
2 novembre 2005 - Aula 716 - Seminario di Analisi Armonica (Astengo)

ore 16:00 - Andrea Carbonaro (Milano)

"Regolarita' massimale Lp per equazioni paraboliche di evoluzione, II."

Abstract: In questo seminario presentero' l'approccio basato sugli integrali singolari al problema della regolarita' massimale Lp per generatori di semigruppi analitici. Dopo aver introdotto il concetto di R-limitatezza, presentero' un recente teorema dei moltiplicatori di tipo Mihlin per moltiplicatori a valori operatoriali su spazi UMD dovuto a N. J. Kalton e L. Weis. Infine parlero' del legame tra calcolo funzionale olomorfo, R-limitatezza e regolarita' massimale lp.
2 novembre 2005 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)
25 ottobre 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - A. Beauville (Nizza)

"Algebraic cycles on Jacobian varieties
"

Abstract: I will describe some recent results about the ring of algebraic cycles
mod. algebraic equivalence on the Jacobian JC of a curve C . This ring
is quite large, and seems to be very difficult to study. I propose to
consider the "tautological subring" obtained by applying natural
operations (sum, intersection product, multiplication by integers...)
starting from the class of C in JC. This ring turns out to be finitely
generated and to have a very interesting structure.

ore 15:45 - A.Verra (Roma3)

"Breve survey sulle trasformazioni di Cremona."

Abstract: Il seminario intende richiamare l'attenzione su un tema classico oggi
meno coltivato: quello delle trasformazioni di Cremona di uno spazio
proiettivo di dimensione qualsiasi. Verranno riconsiderati alcuni ben
noti esempi classici, unitamente a risultati piu' recenti di Ein e
Shepherd-Barron sulle trasformazioni quadro-quadriche e sui loro legami
con la congettura di Hartshorne. Nell'ultima parte si trattera' la
classificazione delle trasformazioni quadro-quadriche di P^4.
21 ottobre 2005 - Aula 713 - Seminario di Analisi Armonica (Astengo)

ore 17:00 - Andrea Carbonaro (Milano)

"Regolarita' massimale Lp per equazioni paraboliche di evoluzione."

Abstract: In questo seminario presentero' l'approccio basato sugli integrali singolari al problema della regolarita' massimale Lp per generatori di semigruppi analitici. Dopo aver introdotto il concetto di R-limitatezza, presentero' un recente teorema dei moltiplicatori di tipo Mihlin per moltiplicatori a valori operatoriali su spazi UMD dovuto a N. J. Kalton e L. Weis. Infine parlero' del legame tra calcolo funzionale olomorfo, R-limitatezza e regolarita' massimale lp.
19 ottobre 2005 - Aula 713 - Seminario di Teoria dei numeri (Perelli)
18 ottobre 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - T.Roemer

"H-vectors of Gorenstein polytopes"

Abstract: Abstract:
We show that the Ehrhart h-vector of an integer Gorenstein polytope
with a unimodular triangulation satisfies McMullen's g-theorem; in
particular it is unimodal. This result generalizes a recent theorem of
Athanasiadis (conjectured by Stanley) for compressed polytopes. It is
derived from a more general theorem on Gorenstein affine normal monoids
M: one can factor K[M] (K a field) by a ``long'' regular sequence in
such a way that the quotient is still a normal affine monoid algebra.
In the case of a polytopal Gorenstein normal monoid E(P), this
technique reduces all questions about the Ehrhart h-vector to a normal
Gorenstein polytope Q with exactly one interior lattice point. If P
has a unimodular triangulation, then it follows readily that the
Ehrhart h-vector of P coincides with the h-vector of the boundary
complex of a simplicial polytope, and the g-theorem applies.
12 ottobre 2005 - Aula 508 - Seminario di Analisi Armonica (Astengo)

ore 16:00 - Alessandro Ottazzi (Berna)

""

12 ottobre 2005 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)
5 ottobre 2005 - Aula 713 - Seminario di Algebra-Geometria (proff. A. Conca, L. Badescu)

ore 14:30 - A. Dubickas (Univ. Vilnius, Lituania)

"Integer and fractional parts of powers of a number"

Abstract: We will discuss the status of several old problems concerning certain
arithmetical properties of the sequence of integral parts [a^n],
n=1,2,3,..., and the location of fractional parts {a^n\}, n=1,2,3,...,
in the interval [0,1), where a is a fixed real number greater than 1.

ore 15:45 - M. Popa (Univ. Chicago, USA)

"Castelnuovo theory and the geometric Schottky problem"

Abstract: Castelnuovo theory is roughly speaking a study of subvarieties in projective space based on analyzing special properties of configurations of points lying on them. This was initiated by the well-known Italian algebraic geometer at the end of the nineteenth century. Around the same time, the Schottky problem emerged: this is the problem of identifying the best known algebraic tori(abelian
varieties), namely Jacobians of curves, among all (principally
polarized) abelian varieties. In its geometric form, the Schottky problem asks for identifying Jacobians based on special properties of the principal polarization, or the theta divisor. In this talk I will explain joint work with G. Pareschi in which we establish a close parallel between these two classical contexts,motivated by modern developments (most notably the Fourier-Mukai transform).
4 ottobre 2005 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)
21 settembre 2005 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)

ore 14:30 - C. Bartocci, D. Brolpasino, I. Scorza (DIMA)

"Rappresentazioni di quivers"

9 settembre 2005 - Aula 713 - Seminario di Analisi Numerica (Piana)
5 luglio 2005 - Aula 705 - Seminario di Didattica (Morselli)

ore 11:00-14:00 - Didattica

21 giugno 2005 - Aula 704 - Seminario di dott. Morselli (Boero)

ore 11:00-14:00 - dott. Morselli

21 giugno 2005 - Aula 713 - Seminario di Algebra-Geometria

ore 14:30 - F. Caselli (Roma/Lione)

"Polinomi di Kazhdan-Lusztig su insiemi parzialmente ordinati
"

Abstract:
20 giugno 2005 - Aula 713 - Seminario di Geometria e Fisica (Bartocci)

ore 14:30 -

"Fibrati di Higgs numericamente piatti"

15 giugno 2005 - Aula 704 - Seminario di Analisi Armonica (Astengo)

ore 10:00 - Francesca Astengo

"Un teorema di estensione di Stein"

ore 11:00 - Emanuela Sasso

"Il semigruppo di Ornstein-Uhlenbeck quantistico"

14 giugno 2005 - Aula 704 - Seminario di Analisi Armonica (Astengo)

ore 14:30 - Filippo De Mari

"Una congettura di Koranyi"

ore 15:30 - Stefano Meda

"BMO per misure prive di proprieta' di raddoppio"

ore 16:30 - Alessandro Veneruso

"Disuguaglianze dispersive per equazioni delle onde sul gruppo di Heisenberg"

13 giugno 2005 - Aula 713 - Seminario di Analisi Numerica (Piana)

ore 11:00-12:00 - M. Piana

8 giugno 2005 - Aula 713 - Seminario di Teoria dei numeri (Perelli)

ore 14:30 - A. Languasco (Univ. Padova)

"Piccole differenze tra primi consecutivi"

7 giugno 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - M. Sala (UCC Cork, Irlanda)

"Decodifica di codici lineari e ciclici: un nuovo approccio"

Abstract: A La decodifica dei codici BCH, e dei codici algebrici in generale, e'
solitamente ottenuta tramite un processo iterativo. Partendo dal lavoro
pioneristico di Chen et al., mostreremo come si possa realizzare una
decodifica alternativa, basata sull'individuazione di un opportuno
polinomio nell'ideale che svanisce sulla varieta' dei sindromi.
L'esistenza di questo polinomio per un generico codice ciclico viene
dedotta dalle proprieta' di una base di Groebner, per ogni codice
ciclico. L'idea puo' essere parzialmente estesa ad altri codici
lineari.
1 giugno 2005 - Aula 704 - Seminario di Analisi Armonica (Astengo)

ore 15:00-16:00 -

"Una funzione massimale su gruppi di tipo NA"

31 maggio 2005 - Aula 713 - Seminario di Algebra-Geometria

Pagina web

ore 14:30 - M. Lattarulo (DIMA)

"Spazi di moduli di curve algebriche reali"

ore 15:45 - A. Del Padrone (DIMA)

""

27 maggio 2005 - aula 715 - Seminario di Teoria delle Categorie (Pagnan)

ore 10:00-11:00 - Pagnan

23 maggio 2005 - Aula 713 - Seminario di Teoria dei Giochi

ore 10:30 - B.Viscolani (University of Padova)

"Advertising Games: New Product Introduction"
joint paper with A.Buratto and L.Grosset
"

ore 12:00 - M.Faillo (University of Trento and St.Anna School of Advances

"Conformist Preferences and Reciprocity in the "Exclusion Game": An Experimental Investigation-
joint paper with L.Sacconi
"

ore 14:30 - S. Benati (University of Trento)

"Problemi di ottimizzazione di portafoglio:Recenti tendenze e problemi aperti"

12 maggio 2005 - aula 715 - Seminario di Problemi inversi

ore 16:30 - prof. M. Piana

"Problemi inversi"

10 maggio 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 15:00 - A. Lopez (Roma III)

"Sull'esistenza di varieta' Q-Fano di dimensione 3
"

Abstract: La teoria di Mori ha messo in risalto come le varieta' di Fano (con
singolarita' al piu' terminali) siano dei mattoni molto importanti per
l'individuazione dei modelli minimali delle varieta'. In dimensione 3
le varieta' di Fano nonsingolari sono classificate, mentre poco si sa
di quelle singolari. Nel seminario si esporranno dei (nuovi) metodi per
limitare i caratteri numerici di tali varieta' (tipicamente il genere
g, dove (-K)^3 = 2g-2) e si mostrera' la dimostrazione di una vecchia
congettura di Fano-Conte-Murre.
5 maggio 2005 - Aula 716 - Seminario di Analisi Numerica

ore 16:00 - M. Piana

"Analisi numerica"

3 maggio 2005 - 508 - Seminario di Seminario dott. Morselli
26 aprile 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - R. Pignatelli (Univ. Trento)

"Fibrazioni di genere basso e superfici con
q=p_g=1.
"

Abstract: Raccontero' di un lavoro in collaborazione con F. Catanese
(math.AG/0503294) nel quale abbiamo dato teoremi di struttura per
fibrazioni (di superfici su curve) di genere 2 e di genere 3 nel caso
di fibra generica non iperellittica, e, tra le applicazioni, abbiamo
studiato le superfici con q=p_g=1, dando una classificazione completa
del caso K^2=3 (in particolare rispondendo negativamente ad una
congettura di Catanese e Ciliberto).
22 aprile 2005 - Aula 705 - Seminario (Piana)

ore 15:00 - Prof. Miller

"Computerized tomography from X-rays in 2-D and in 3-D"

Abstract: Abstract: We consider old results on 2-D computerized tomography
methods and their relevance to new fully 3-D problems. We examine
the 2-D filtered back-projection method (FBP) from several perspectives
to better understand how it works. Based on that understanding, we
question whether highly stable, reliable reconsturction algorithms can
be found for wide-detector cone-beam 3-D machines with their resulting
large-slant beams. We illustrate with numerically derived kernels for
a model slant-beam problem. We also consider a "change of variables"
method for the 2-D fan-beam problem and advocate a method for 4-D data
in 3-D reconstruction.
19 aprile 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - C.Viola (Univ. Pisa)

"Trasformazioni birazionali e integrali Euleriani"

Abstract: Nell'opera di Eulero, in relazione all'integrale euleriano di seconda
specie (secondo la terminologia introdotta da Legendre) che definisce
la funzione gamma, si considerano integrali di prima specie, cioe`
integrali definiti fra 0 e 1 di certe funzioni razionali che si
annullano con molteplicita` in 0 e in 1. Opportune generalizzazioni al
caso multidimensionale degli integrali euleriani di prima specie si
sono recentemente rivelate di grande importanza per ottenere proprieta`
di irrazionalita` per costanti classiche. Lo scopo di questo seminario
e` dare una rassegna su un metodo recente, dovuto a Rhin e Viola,
basato sull'azione di gruppi di trasformazioni birazionali e di gruppi
di permutazioni su integrali euleriani multidimensionali.
13 aprile 2005 - Aula 706 - Seminario

ore 14:30-18:00 -

"Philosophies and Techniques for Promoting Student Engagement, Deep Conceptual Understanding, Analytical Skills, and Critical Thinking in Math Courses
"

Abstract:
12 aprile 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - Boij (Stoccolma)

"Gorenstein and level quotients"

Abstract:

ore 15:45 - J. Kaczorowski (Poznan, Polonia)

"Universality property of L-functions.
"

Abstract: One says that an L-function has universality property if inside the
critical strip its shifts approximate every given holomorphic function
with arbitrary precision. Generalizations include "joint universality"
and "joint shift universality". The lecture will start with a short
discussion of universality of classical L-functions and then will focus
on some recent developments of the subject including applications to
the Selberg class.
6 aprile 2005 - Aula 704 - Seminario (Zolezzi)

ore 15:00 - Dott. Silvia Villa (Univ. Firenze)

"Well Posed Problems of the Calculus of Variations"

5 aprile 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - prof. F. Catanese (Univ. Bayereuth)

""

Abstract: Nella teoria della classificazione della varieta' algebriche (o piu' generalmente varieta' complesse compatte), e' d'uso considerare due varieta' lisce equivalenti se esse sono tra loro birazionali, oppure sono deformazione l' una dell' altra. Un invariante per tale classificazione e' la dimensione di Kodaira, che per le curve assume valore 1 se e solo se il genere g e' almeno 2. Tale considerazione suggerisce di considerare piu' generalmente varieta' a singolarita' canoniche, e la relazione di equivalenza QED = Quasi Etale Deformation generata da
1) trasformazioni birazionali
2) deformazioni
3) morfismi quasi etale, ovvero ramificati solo su un sottinsieme di codimensione almeno due della varieta' di partenza.
Un recente teorema di Siu garantisce che per varieta' algebriche la dimensione di kodaira e' un invariante per la equivalenza QED.
Un interessante teorema e' allora il seguente: le classi di QED equivalenza di curve o superficie speciali coincidono con il dato della dimensione e della dimensione di Kodaira.
Un risultato simile vale anche per le superficie Kaehleriane, non vale per le superficie non Kaehleriane ( le superficie di Hopf sono stabili
per equivalenze QED) e probabilmente non vale per le superficie di tipo generale.
Le relazioni di equivalenza QED pongono in ogni caso nuovi interessanti problemi.

ore 15:45 - prof. M. Kreuzer (Univ. Dortmund)

""

Abstract:
22 marzo 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - prof. M. Bertolini (Univ. Pavia)

"(titolo da comunicare)"

prof. W. Bruns (Univ. Osnabrueck)

"A generalization of the Grassmannian"

17 marzo 2005 - Aula 716 - Seminario di Algebra-Geometria (Conca)

ore 15:45 - A. Rosenschon (Univ. Bufalo)

"Torsion and Cotorsion in cohomology theories"

Abstract: We show that for a wide range of cohomology theories including motivic cohomology and algebraic K-theory, torsion and cotorsion is invariant under certain field extensions k\subset K. This generalizes results of Suslin and Suslin-Voevodsky.
15 marzo 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - prof. M. Sombra (Univ. Barcelona)

"Height of projective toric varieties"

Abstract: The height of a subvariety $X \subset \mathbb{P}^N$ is a measure of the bit complexity of a symbolic representation of $X$, encoded via its Chow form. This notion generalizes the height of points widely applied in diophantine approximation. In higher dimensions, it behaves like an arithmetic analog of the degree. In this talk I will present an explicit expression for the canonical (or normalized) height of a projective toric variety. This expression decomposes as a sum of local contributions, each term being the integral of a certain function, piecewise affine and concave. The introduced set of functions behaves as an arithmetic analog of the polytope classically associated with the torus action. Besides the formulae for the height, we show that this object behaves naturally with respect to several standard constructions: joins, Segre products, Veronese embeddings, decomposition into orbits. If time allows, I will also present the arithmetic BKK theorem, itself a consequence of the aforementioned results.

ore 15:45 - Prof. R. D'Agnolo (Univ. Padova)

"Algebroidi di operatori microdifferenziali"

Abstract:
14 marzo 2005 - Aula 713 - Seminario di Teoria dei Giochi

ore 10:30 - Prof. L. Gardini (Ist. Scienze Economiche Univ. Urbino)

"Global bifurcations of invariant curves in duopoly games."

Abstract: The talk deals with some global bifurcations occurring in two dimensional maps associated with closed invariant curves (attracting and/or repelling), which are not related to the local Neimark-Hopf bifurcation (supercritical or subcritical). By using a duopoly model we shall see several possible mechanisms which lead to the appearance or disappearance of invariant closed curves, which are associated with a saddle connection or a
homoclinic loop.

ore 12:00 - prof. I. Sushko (Institute of Mathematics National Academy of Sciences of Ukraine) sushko@imath.kiev.ua

"Cournot duopoly models with kinked demand functions."

Abstract: Dynamical systems generated by piecewise linear maps are interesting both from theoretical and applied points of view. Bifurcation theory of such systems differs from the smooth case: Such well-known bifurcations as
saddle-node, flip, Neimark bifurcations and others, change their nature, as well as particular bifurcations, like border-collision, play an important role. In this talk we shall see some border-collision bifurcations in a Cournot duopoly model with piecewise linear discontinuous reaction functions, and we shall prove the existence of a chaotic attractor.

ore 14:30 -

"Economic Exploitation of renewable Resources: a dynamical analysis."

Abstract: Following recent contributions to the literature on common pool exploitation, models of commercial fishing are developed and employed to analyze the main consequences of various harvesting policies on the extinction or conservation of natural resources. The models incorporate, in a discrete-time setting, the microeconomic decisions of different groups of fishermen who compete in oligopolistic markets of the harvested resource. Among the various alternative methods of fishery regulation we deal with the institution of reserve zones where fishing is prohibited, and in general with the presence of areas with different exploitation policies.
8 marzo 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - prof. L. Caporaso (Univ. Roma 3)

"Modelli di Neron sullo spazio dei moduli delle curve stabili."

Abstract:

ore 15:45 - prof. C. Traverso (Univ. Pisa)

"Un giornale attivo, problemi e soluzioni."

Abstract: Un giornale attivo e' un giornale in forma elettronica che permetta di includere in un articolo del codice funzionante. Si descrivera' un progetto in corso nell'ambito del progetto "Algebra commutativa e computazionale" per un giornale attivo in algebra computazionale, e si illustreranno alcune scelte, come il modello di software libero che si vuole adottare, basato su di una estensione della distribuziole Linux Knoppix, le motivazioni e i problemi relativi.
2 marzo 2005 - Aula 508 - Seminario

Pagina web

ore 17:00 - dott. Hennie Poulisse (Capo Ricercatore al Centro Ricerche della Shell - Rijswijk, Olanda)

"Mathematical Developments in Oil - and Gas Exploration and Production"

Abstract: The presentation starts by highlighting a number of subjects that traditionally, and still today, are the bulk of the research activities in oil industry, notably in the fields of geophysics - exploration - and flow through porous media - production. Specifically after brief problem descriptions in these areas, the - partial differential - equations associated with these problems are presented, as well as the applications resulting from solving these equations. Because the diversity of the different applications is emphasized, the character will be that of a "guided tour", rather than getting specific. In the midst of the 1990's an important problem in production operations, namely the duration and evaluation of an oil well production test, was formulated and solved in terms of a mathematical stopping time problem without any recourse to a physical model. This marked the beginning of a New Development in parallel to the traditional ones, resulting in an application that monitors and controls the production of oil - and gas wells and that is being rolled out globally throughout the Shell group. This application is very much in the realm of the - topology of - dynamical systems, and takes in only information that is provided
by the local technical infrastructures through measurements. An excerpt is presented of the discussions, still on-going today, that sparkled this New Development. What these applications thus far have in common is that sooner or later virtually all of them have to pass a Gate over which is written: "Numerical Linear Algebra". To put it bluntly, we could say that regardless of their origin, most of the challenges we are facing have to fit 'at the end of the day' into the structure of vector spaces from linear algebra, with real - or complex numbers operating as scalars upon them.
The thought that for some problem the Gate may be too narrow seems inescapable. From a purely mathematical point of view widening the Gate is the logical step from generalizing the vector spaces to modules.
Spectacular developments in Algebra, specifically in Computational Commutative Algebra that are taking place roughly since the 1990's, have made it possible to also realize this generalization, and hence giving rise to a 'second generation' of the New Developments in exploration - and production research. The University of Genoa is, together with the University of Dortmund in Germany, a key player in this new mathematical development in this research area, specifically through their development of the computer algebra system CoCoA. It will be made clear that in this
new development an "oil - and gas system" is no longer an anonymous object that generated the data, thereby expunging the larger part of the criticism from the "physical modellers"on this approach.
Also the new challenges we are facing around algebraic problems with empirical data are discussed briefly. The presentation ends with a short exposition of the CoCOil project, the by Shell sponsored cooperation with the universities of Genoa and Dortmund, in which in a four years research program an impressive number of problems are addressed in this new context, including major problems like increasing the ultimate recovery, that is producing a larger portion of the known reserves.
1 marzo 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 15:00 - prof. L. Gruson (Univ. Versailles)

"Action of the linear group on germs of smooth curves in the projective space"

Abstract: Let (C,x) be an analytic curve with a marked point in a projective space P of dimension n . The use of the unique rational normal curve passing to x "thickened" (n+3) times on C allows in general to find an almost canonical base of P (there is left a Z/3Z -action) and an (irrational) canonical parametrization of C near x . This has been noticed by Halphen and used by him to study several classes of linear differential equations. I will try to made explicit some of his ideas.
28 febbraio 2005 - Aula 706 - Seminario di Analisi Armonica (Astengo)

ore 15:00 - Dott. Andrea Carbonaro (Univ. Milano)

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22 febbraio 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - Le Dung Trung ICTP, Trieste)

"A geometrical understanding of Multiplicity.Abstract: In this lecture we shall indicate how one calculates the multiplicity of a primary ideal as an intersection number."

A. Tironi (Univ. Milano)

"Reducible hyperplane sections of smooth complex projective manifolds"

Abstract: Let X be a smooth n-dimensional algebraic submanifold of P^N (over the complex field). Many classical results describe the structure of X under assumption on one of its irreducible hyperplane sections. The goal of this talk is to discuss what happens when the intersection of the above X with some hyperplane is a union of two
smooth divisors meeting transversally, each of which has a curve section of low genus. We show that such a problem becomes progressively easier as the dimension of X increases and when n=3, some partial results are given.
18 febbraio 2005 - Aula 705 - Seminario di Analisi Armonica (Astengo)

ore 15:00 - Dott. Andrea Carbonaro (Univ. Milano)

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15 febbraio 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - prof. P. Ionescu (Univ. Bucarest)

15 febbraio 2005 - Aula 713 - Seminario di Algebra-Geometria (Conca)

ore 14:30 - prof. P. Ionescu (Univ. Bucarest)

"Secant defective manifolds"

Abstract: We review some classical facts about secant defective manifolds due to Severi, Scorza et.al. We recall Hartshorne's Conjecture, Zak's linear normality theorem and the classification of Severi varieties. The recent theory of "Quadratic Entry Locus Varieties" ( QEL for short) , due to F. Russo, is briefly described. Joint recent work with Russo on the classification of QEL's is explained. prof. A. Tonolo (Univ. Padova)

""

Abstract: Si intende introdurre le teorie di equivalenza e dualita' associate ai bimoduli tilting e cotilting,
per poi analizzare con maggior dettaglio le correlazioni tra le teoria di dualita' associate ai bimoduli cotilting su anelli noetheriani non necessariamente commutativi ed ai moduli canonici su anelli di Cohen - Macaulay.
25 ottobre 2004 - Aula 713 - Seminario

ore 15:00 - prof. Rodica Branzei (Univ. Iasi - Bulgaria)

"The equal split-off set for cooperative games with trasferable utility"

Abstract: This talk with a new set-valued egalitarian solution concept for cooperative games with trasferable utility (TU-games) which we call the Equal Splitt-Off Set (ESOS). An easy to implement procedure to comnpute any ESOS allocation is presented. This procedure relies on Duffa-Ray
algorithm for computing the constrained egalitarian solution for a convex games.
We investigate with respect to the ESOS the domain of properties which are desirable for (egalitarian) solution concepts for TU-games.
17 febbraio 2004 - Aula 716 - Seminario

ore 15:00 - prof. A. Ioffe (Univ. Haifa)

"On the radius of metric regularity of infinite dimensional maps"