|
Mardi 5 Janvier
| Heure: |
13:00 - 14:00 |
| Lieu: |
Sans doute en ligne (à confirmer). |
| Résumé: |
MB - Unified approach to fluid approximation of linear kinetic equations with heavy tails - |
| Description: |
Émeric Bouinanomalousit is a governed
by a fractional diffusion equation. Lebeau and Puel proved
last year the first similar result for Fokker-Planck operator,
in dimension 1 and assuming that the equilibrium distribution
has finite mass. Fournier and Tardif gave an alternative
probabilistic proof, more general (covering any dimension and
infinite-mass equilibrium distribution) but non-constructive.
We present a unified elementary approach, fully quantitative,
that covers all previous cases as well as new ones. This is a
joint work with Clément Mouhot (University of Cambridge). |
Jeudi 7 Janvier
| Heure: |
10:00 - 11:30 |
| Lieu: |
Exposé en ligne |
| Résumé: |
Topologie algébrique - Moduli spaces of curves and Grothendieck-Teichmuller group - |
| Description: |
Geoffroy Horel |
Vendredi 8 Janvier
| Heure: |
13:00 - 13:30 |
| Lieu: |
Salle B407, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
Modélisation et Calcul Scientifique - An introduction to Balanced Viscosity solutions to (multi)rate-independent systems - |
| Description: |
Riccarda Rossi |
| Heure: |
15:30 - 16:30 |
| Lieu: |
en ligne |
| Résumé: |
PM - EDP - Sharp constant in the curl inequality and ground states for curl-curl problem with critical exponent - |
| Description: |
Jaroslaw MederskiSharp Sobolev-type inequalities have been widely studied by a large
number of authors and the best Sobolev constants play an important role
e.g. in mathematical physics. |
| Heure: |
15:30 - 16:30 |
| Lieu: |
en ligne |
| Résumé: |
Équations aux Dérivées Partielles non-linéaires - Sharp constant in the curl inequality and ground states for curl-curl problem with critical exponent - |
| Description: |
Jaroslaw MederskiSharp Sobolev-type inequalities have been widely studied by a large
number of authors and the best Sobolev constants play an important role
e.g. in mathematical physics. |
Jeudi 14 Janvier
| Heure: |
10:00 - 11:30 |
| Lieu: |
Exposé en ligne |
| Résumé: |
Topologie algébrique - A model for homotopy E?cooperads - |
| Description: |
Lorenzo Guerra
ing, homotopies are incorporated into the associativity conditions of operadicwe describe a notion of Segal Hopf cooperads in their strict and homotopy verEalgebras. Their interest lies, at least in part,E-In the first part of the talk, that will (mostly) have an expository flavour, I recall Mandell’s theorem, and I will state some of our results. In the second and I will tentatively provide an outline of some proofs. |
Vendredi 15 Janvier
| Heure: |
10:30 - 11:30 |
| Lieu: |
Exposé en distanciel |
| Résumé: |
Géométrie Arithmétique et Motivique - The p-part of BSD for rational elliptic curves at Eisenstein primes - |
| Description: |
Giada GrossiLien researchseminars.org |
| Heure: |
14:00 - 15:00 |
| Lieu: |
https://bbb.math.univ-paris13.fr/b/emm-mwh-ajj |
| Résumé: |
Modélisation et Calcul Scientifique - Autour de la détection de perturbations par imagerie - |
| Description: |
Jérémi Heleine
Lien pour assister au séminaire : https://bbb.math.univ-paris13.fr/b/emm-mwh-ajj |
| Heure: |
15:30 - 16:30 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
PM - EDP - Propagation of chaos and corrections to mean field for classical interacting particles - |
| Description: |
Mitia DuerinckxWe consider a system of classical particles, interacting via a smooth,
long-range potential, in the mean-field regime, and we analyze the
propagation of chaos in form of sharp estimates on many-particle
correlation functions. While approaches based on the BBGKY hierarchy are
doomed by uncontrolled losses of derivatives, we propose a novel
non-hierarchical approach that relies on discrete stochastic calculus
with respect to initial data. This result allows to rigorously truncate
the BBGKY hierarchy to an arbitrary precision on the mean-field
timescale, thus justifying the so-called Bogolyubov corrections to mean
field. As a by-product, we also discuss the justification of the
Lenard-Balescu relaxation for a spatially homogeneous system. |
| Heure: |
15:30 - 16:30 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
Équations aux Dérivées Partielles non-linéaires - Propagation of chaos and corrections to mean field for classical interacting particles - |
| Description: |
Mitia DuerinckxWe consider a system of classical particles, interacting via a smooth,
long-range potential, in the mean-field regime, and we analyze the
propagation of chaos in form of sharp estimates on many-particle
correlation functions. While approaches based on the BBGKY hierarchy are
doomed by uncontrolled losses of derivatives, we propose a novel
non-hierarchical approach that relies on discrete stochastic calculus
with respect to initial data. This result allows to rigorously truncate
the BBGKY hierarchy to an arbitrary precision on the mean-field
timescale, thus justifying the so-called Bogolyubov corrections to mean
field. As a by-product, we also discuss the justification of the
Lenard-Balescu relaxation for a spatially homogeneous system. |
Lundi 18 Janvier
| Heure: |
14:00 - 18:00 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
Analyse semi-classique & Physique mathématique - Problèmes Spectraux en Physique Mathématique - |
| Description: |
Séminaire tournant |
| Heure: |
14:00 - 18:00 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
EDP & Physique mathématique - Problèmes Spectraux en Physique Mathématique - |
| Description: |
Séminaire tournant |
Jeudi 21 Janvier
| Heure: |
10:00 - 11:00 |
| Lieu: |
Séminaire en ligne |
| Résumé: |
Topologie algébrique - Minimal models for graphs-related operadic algebras - |
| Description: |
Jovana ObradovicWe construct explicit minimal models for the (hyper)operads governing modular, |
Vendredi 22 Janvier
| Heure: |
10:30 - 12:00 |
| Lieu: |
Exposé en distanciel |
| Résumé: |
Géométrie Arithmétique et Motivique - Around the conjectures of Mazur and Rubin on the distribution of modular symbols - |
| Description: |
Asbjørn NordentoftLien researchseminars.org |
| Heure: |
15:30 - 16:30 |
| Lieu: |
Visioséminaire |
| Résumé: |
PM - EDP - Co-dimension one stable blowup and threshold phenomena for supercritical wave equations - |
| Description: |
Birgit Schörkhuber
Self-similar solutions play an important role in the dynamics of nonlinear evolution equations and can provide explicit examples for the formation of singularities in finite time. This talk is concerned with wave equations with a focusing power nonlinearity in the so-called energy supercritical case. These rather simple models serve as toy problems for more involved field equations from theoretical physics. After a brief summary of known results on blowup dynamics for this class of equations, I will present new explicit examples of self-similar solutions for the wave equation with a cubic, respectively, a quadratic nonlinearity. I will discuss methods to analyse the stability of these solutions and show that they are co-dimension one stable modulo symmetries. Furthermore, we discuss their role in the characterization of the threshold between finite-time blowup and global existence. |
| Heure: |
15:30 - 16:30 |
| Lieu: |
Visioséminaire |
| Résumé: |
Équations aux Dérivées Partielles non-linéaires - Co-dimension one stable blowup and threshold phenomena for supercritical wave equations - |
| Description: |
Birgit Schörkhuber
Self-similar solutions play an important role in the dynamics of nonlinear evolution equations and can provide explicit examples for the formation of singularities in finite time. This talk is concerned with wave equations with a focusing power nonlinearity in the so-called energy supercritical case. These rather simple models serve as toy problems for more involved field equations from theoretical physics. After a brief summary of known results on blowup dynamics for this class of equations, I will present new explicit examples of self-similar solutions for the wave equation with a cubic, respectively, a quadratic nonlinearity. I will discuss methods to analyse the stability of these solutions and show that they are co-dimension one stable modulo symmetries. Furthermore, we discuss their role in the characterization of the threshold between finite-time blowup and global existence. |
Lundi 25 Janvier
| Heure: |
14:00 - 15:30 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
Analyse semi-classique & Physique mathématique - Opérateurs de Schrödinger aléatoires stationnaires à petit désordre. - |
| Description: |
Christopher Shirley Dans cet exposé nous allons étudier les opérateurs de Schrödinger avec
potentiel stationnaire et étudier l'existence d'ondes de Bloch
stationnaires pour différent type de stationnarité et en particulier
dans le cas aléatoire. |
| Heure: |
14:00 - 15:30 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
EDP & Physique mathématique - Opérateurs de Schrödinger aléatoires stationnaires à petit désordre. - |
| Description: |
Christopher Shirley Dans cet exposé nous allons étudier les opérateurs de Schrödinger avec
potentiel stationnaire et étudier l'existence d'ondes de Bloch
stationnaires pour différent type de stationnarité et en particulier
dans le cas aléatoire. |
Mercredi 27 Janvier
| Heure: |
13:30 - 15:00 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
Théorie Ergodique et Systèmes Dynamiques - Renormalisation des flots sur les surfaces et des échanges d'intervalles généralisés - |
| Description: |
Selim Ghazouani
Renormalisation des flots sur les surfaces et des échanges d'intervalles
généralisés
Les travaux d'Arnol'd, Herman,  Yoccoz et autres constituent une théorie
complète des propriétés géométriques des difféomorphismes du cercle et
de manière presque équivalente des flots sur le tore.
Après avoir rappelé des éléments de cette théorie, j'essayerais de
présenter les problèmes équivalents pour les surfaces de genre supérieur
et leur applications unidimensionelles associées, les échanges
d'intervalles généralisés. |
Vendredi 29 Janvier
| Heure: |
10:30 - 12:00 |
| Lieu: |
Exposé en distanciel |
| Résumé: |
Géométrie Arithmétique et Motivique - Derived Galois deformation rings - |
| Description: |
Yichang CaiLien researchseminars.org |
| Heure: |
14:00 - 15:00 |
| Lieu: |
https://bbb.math.univ-paris13.fr/b/emm-mwh-ajj |
| Résumé: |
Modélisation et Calcul Scientifique - Une analyse de convergence pour GMRES appliquée aux équations intégrales de frontière pour l’équation d’Helmholtz en présence de cavités elliptiques - |
| Description: |
Pierre Marchand |
| Heure: |
15:30 - 16:30 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
PM - EDP - On the drift conformal method in General Relativity - |
| Description: |
Caterina VâlcuWe study initial data in General Relativity, which are defined as
solutions to the constraint equations. The focus in this talk is a
modified version of the conformal method proposed by David Maxwell.
While the model seems more strongly justified from a geometrical
standpoint, the resulting system becomes significantly moreWe study initial data in General Relativity, which are defined as
solutions to the constraint equations. The focus in this talk is a
modified version of the conformal method proposed by David Maxwell.
While the model seems more strongly justified from a geometrical
standpoint, the resulting system becomes significantly more difficult to
solve; it presents critical nonlinear terms, including gradient terms.
We describe existence and stability while working in dimensions 3,4 and
5, under smallness assumptions and in the presence of a scalar field
with positive potential. The tools we use are related to obtaining a
priori estimates (compactness results) and a fixed-point theorem. |
| Heure: |
15:30 - 16:30 |
| Lieu: |
Salle B405, bâtiment B, LAGA, Institut Galilée, Université Paris 13 |
| Résumé: |
Équations aux Dérivées Partielles non-linéaires - On the drift conformal method in General Relativity - |
| Description: |
Caterina VâlcuWe study initial data in General Relativity, which are defined as
solutions to the constraint equations. The focus in this talk is a
modified version of the conformal method proposed by David Maxwell.
While the model seems more strongly justified from a geometrical
standpoint, the resulting system becomes significantly moreWe study initial data in General Relativity, which are defined as
solutions to the constraint equations. The focus in this talk is a
modified version of the conformal method proposed by David Maxwell.
While the model seems more strongly justified from a geometrical
standpoint, the resulting system becomes significantly more difficult to
solve; it presents critical nonlinear terms, including gradient terms.
We describe existence and stability while working in dimensions 3,4 and
5, under smallness assumptions and in the presence of a scalar field
with positive potential. The tools we use are related to obtaining a
priori estimates (compactness results) and a fixed-point theorem. |
|
|
