COLLOQUES et SEMINAIRES 2013

(Tous les colloques sont suivis d'un apéritif au Z-Bar)

Séminaire "Topologie et Géométrie"
Rinat Kashaev (UniGe)
"Une nouvelle formulation de la TQFT de Teichmüller"
Résumé :
En utilisant la transformée de Weil-Gel'fand-Zak de dilogarithme quantique de Faddeev, je décrirai un nouveau modèle de la TQFT de Teichmüller défini sur les triangulations formées, où les variables d'état sont associées aux arêtes de triangulation et prennent leurs valeurs dans le cercle. C'est un travail récent en collaboration avec J.E. Andersen, arXiv:1305.4291.
Jeudi 3 octobre à 14h15, salle 17

Soutenance de thèse
Yves Barmaz (UniGe)
"Applications of the Batalin-Vilkovisky Geometry: Dualities and Chern-Simons Theory with Boundary"
Sous la direction du Prof. A. Alekseev
Jeudi 3 octobre à 16h15, Villa Battelle
La thèse sera suivie d'un apéritif. Venez nombreux!

Séminaire "Math physique"
Yacine Ikhlef (LPTHE, Université Pierre et Marie                                              Curie/CNRS)
Titre : "Discrete parafermions and quantum-group symmetries
Abstract :
In two-dimensional statistical models, discrete parafermions are non-local operators which satisfy a lattice version of the Cauchy-Riemannn (CR) equations, and they can be used to establish rigorously the scaling limits of interfaces and correlation functions. The relation between this notion and that of integrability has been a challenging puzzle. For models with an underlying quantum-group symmetry, I will explain how to obtain systematically the discrete parafermions, starting from the Bernard-Felder construction of non-local conserved currents.
Lundi 7 octobre 2013 à 16h15, salle 17


Séminaire "Groupes et Géométrie"
Dieter Kotschick (Munich)
"Fundamental groups of Kähler manifolds and combinatorial group theory"
Abstract : The study of fundamental groups of Kähler manifolds is a fascinating enterprise at the crossroads of various branches of geometry and topology, with strong relations to algebra and analysis as well. This lecture will survey some recent developments in this area, focussing on applications of the so-called Albanese map (which will be introduced during the lecture). Several results pertaining to groups of interest in low-dimensional topology and in combinatorial and geometric group theory will be discussed.
Mardi 8 octobre 2013 à 10h30, salle 623

Séminaire "Topologie et Géométrie"
Mounir Benheddi (UniGe)
"The Conway function and link Floer homology"
Résumé:
The Alexander polynomial is one of the oldest computable
invariants of oriented colored links. In this talk, I will adress two
particular models of that polynomial: the Conway function and the Euler
characteristic of link Floer homology. After describing these two
models, I will explain how one proves that they coincide.
Jeudi 10 octobre 2013 à 14h15, salle 17

Colloque
David Cimasoni (UniGe)
"Basic Notions: Ce que l'homologie peut faire"
Résumé :
Le but de cet exposé est de partir de la théorie de l'homologie
sous sa forme axiomatique, sans en démontrer l'existence, et d'en
déduire un maximum de résultats topologiques:
théorème du point fixe de Brouwer,
invariance de la dimension, sphères poilues, algèbres à
division, théorème du sandwich,...
Aucune connaissance préalable en topologie algébrique n'est requise.
Jeudi 10 octobre à 16h15, salle 17

Séminaire "Groupes et Géométrie"
Tommaso Terragni
"On the growth series of a Coxeter group"
Abstracts:
Let $(W,S)$ be a finitely generated Coxeter group and let $p_{(W,S)}(t)$ be its Poincar\'e series, i.e., the growth function of $W$ with respect to the Coxeter generating set $S$.
In the first part of my talk I will  give a cohomological interpretation of $p_{(W,S)}(t)$, which is normally computed as, and considered a combinatorial object.
Then, I will discuss some work-in-progress about the growth of (non-spherical, non-affine) Coxeter groups and their exponential growth rate.
Mardi 15 octobre 2013 à 13h15, salle 623
(Attention horaire inabituel)

Colloque
Laure Saint-Raymond (ENS, Paris)
"From Newton's dynamics to the heat equation"
Abstract :
The goal of this lecture is to show how the Brownian motion can be derived rigorously from a deterministic system of hard spheres in the limit where the number of particles tends to infinity, and their diameter
simultaneously converges to 0.
As suggested by Hilbert in his sixth problem, we will use the linear
Boltzmann equation as an intermediate level of description for the
dynamics of one tagged particle.
We will discuss especially the origin of irreversibility, which is a
fundamental feature of both the Brownian motion and the Boltzmann equation, and which has no counterpart at the microscopic level.
Thursday, October 17, 2013, 16:15, room 17

Séminaire "Math physique"
Noam Berger (Technische Universität München)
"Local limit theorem for ballistic random walk in random environments"
Abstract:
We prove a version of a local CLT for random walk in random
environments satisfying Sznitman’s ballisticity condition (T’) in dimension four and higher.
This is joint work with Moran
Lundi 28 octobre 2013 à 16h15, salle 17

Université de Genève
Section de Mathématiques
2-4, rue du Lièvre
CH-1227 Genève-Acacias
Tél. +4122 379 11 51
Fax +4122 379 11 76
E-mail :
Najat.Martinez@unige.ch
Mervat.Cluzeau@unige.ch
Isabelle.Cosandier@unige.ch