Geometria_Pisa September 2022

geometria_pisa@lists.dm.unipi.it

3 participants
3 discussions

Seminario 27/10/2021
by Tamas Szamuely 25 Nov '22

25 Nov '22

Cari tutti, ecco il programma del prossimo seminario di geometria algebrica e aritmetica di Pisa: Mercoledì 27 ottobre 2021, Dipartimento di matematica, Aula Magna 15:00--16:00 Valerio Melani (Pisa): The Poisson structure on the affine Grassmannian via derived algebraic geometry Motivated by a conjecture of Kapranov-Ginzburg-Vasserot, we will explain how to reinterpret the classical Poisson structure on the affine Grassmannian using tools from derived symplectic (and Poisson) geometry. Our approach is based on the study of symplectic structures on derived stacks whose cotangent complex is not perfect, and therefore uses in a crucial way the formalism of Tate modules. The talk is based on joint work with Mauro Porta and Pavel Safronov. Homepage del seminario: http://pagine.dm.unipi.it/tamas/saga.html Migliori saluti, Tamás Szamuely

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[Indico] Lorenzo Venturello, Flag spheres and $\gamma$-positivity, 06/10/2022, 15:00 Europe/Rome
by francesco.sala＠unipi.it 30 Sep '22

30 Sep '22

Title: Flag spheres and $\gamma$-positivity, Speaker(s): Lorenzo Venturello, Università di Pisa, Date and time: 6 Oct 2022, 15:00 (Europe/Rome), Lecture series: Seminar on Combinatorics, Lie Theory, and Topology, Venue: Department of Mathematics (Aula Magna). You can access the full event here: https://events.dm.unipi.it/e/107 Abstract -------- The $f$-vector of a simplicial complex is the vector whose entries record the number of faces in each dimension. It is typically convenient to study an integer linear transformation of the $f$-vector, called the $h$-vector, which naturally appears in the Hilbert series of an algebra associated to the simplicial complex. When we impose additional topological or combinatorial property on the complex, we observe linear relations or inequalities among the entries of the $h$-vector. For instance, when the complex triangulates a sphere, the $h$-vector is nonnegative, palindromic and unimodal. In this talk I will focus on a special family of triangulated spheres called flag and I will introduce a conjecture due to Gal which predicts precise linear inequalities which are stronger then thos ein the case of arbitrary spheres. Gal's inequalites can be conveniently encoded as statements of nonnegativity of a third integer vector, called $\gamma$-vector. I will show that a natural algebraic generalization of this conjecture does not hold (joint work with Alessio D'Alì) and comment on a reduction strategy proposed by Chudnowsky and Nevo (joint work in progress with Geva Yashfe). Finally, if time permits, I will present recent progress on a different $\gamma$-positivity problem involving triangulations of symmetric edge polytopes of a graph (joint work with Alessio D'Alì, Martina Juhnke-Kubitzke and Daniel Köhne). -- Indico :: Email Notifier https://events.dm.unipi.it/e/107

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Seminario sistemi dinamici giovedì prossimo
by Bruno Martelli 12 Sep '22

12 Sep '22

Carissimi, Inoltro avviso di seminario per giovedì prossimo, A presto, Bruno Martelli Carissimi, vi segnalo il seguente seminario che sarà tenuto da Fabrizio Bianchi (Université de Lille) in Sala Seminari giovedì 15 settembre alle ore 14:00: Holomorphic motions of Julia sets: dynamical stability in one and several complex variables Abstract: We discuss the stability of holomorphic dynamical systems under perturbation. In dimension 1, the theory is now classical and is based on works by Lyubich, Mané-Sad-Sullivan and DeMarco. I will review this theory and present a recent generalisation valid in any dimension. Since classical 1-dimensional techniques no longer apply in higher dimensions, our approach is based on ergodic and pluripotential methods. Pur essendo inserito nel ciclo di seminari di Sistemi Dinamici, penso possa essere di interesse anche per i geometri. Ciao e a presto, Marco Prorettore per la Didattica Università di Pisa ********************************************************** Marco Abate Tel: +39/050/2213.230 Dipartimento di Matematica Fax: +39/050/2210.678 Universita' di Pisa Largo Pontecorvo 5 E-mail: marco.abate(a)unipi.it <marco.abate(a)unipi.it> 56127 Pisa Italy Web: pagine.dm.unipi.it/abate/ **********************************************************

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Geometria_Pisa September 2022