Probability and analysis informal seminarThe 2D XY model has attracted attention of physicists and mathematicians for several decades. One way to understand this model is through its dual height function. Recent developments make it possible to show that the phase transitions of the two models coincide. At the core of the proof is a new perspective on the Symanzik/Brydges–Fröhlich–Spencer random walk. The talk is based on arXiv:2301.06905 (Bijecting the BKT transition) and arXiv:2211.14365 (A dichotomy theory for height functions).  ========Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: « subscribe seminaire_mathematique PRENOM NOM »(indiquez vos propres prénom et nom) et laissez le corps du message vide.

Probability and analysis informal seminarWe consider supercritical bond percolation on $Z^d$ and study the chemical distance, i.e., the graph distance on the infinite cluster. It is well-known that there exists a deterministic constant μ(x) such that the chemical distance D(0,nx) between two connected points 0 and nx grows like nμ(x). We prove the existence of the rate function for the upper tail large deviation event {D(0,nx)>nμ(x)(1+ϵ),0↔nx} for d>=3.  Joint work with Shuta Nakajima.  ========Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: « subscribe seminaire_mathematique PRENOM NOM »(indiquez vos propres prénom et nom) et laissez le corps du message vide.

I will discuss explicit M(em)-brane solutions (including some non-commutative ones), relations to hydrodynamics, singularity-formation, and aspects of integrability  Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: « subscribe seminaire_mathematique PRENOM NOM »(indiquez vos propres prénom et nom) et laissez le corps du message vide. 

Advances in Nonlinear Analysis and Nonlinear WavesFrank Merle, a mathematician, and holder of the Université de Cergy-Pontoise – IHES Chair in Analysis has made many important and seminal contributions to the qualitative study of solutions of nonlinear partial differential equations coming from Physics. Merle’s work has been pioneering in the sharp analysis of blowup solutions, and the collision of solitons, as well as in the soliton resolution conjecture. His groundbreaking works have been very influential in the field and beyond.Throughout his career, Frank Merle received many distinctions, including:ICM Invited Speaker (1998)Bôcher Memorial Prize – American Mathematical Society (2005)Silver Medal – Centre National de la Recherche Scientifique (2005)ERC Advanced Grant « Blow-up, Dispersion and Solitons » (2011)ICM Plenary Speaker (2014)Grand prix Ampère de l’électricité de France – French Academy of Sciences (2018)Member of the Academia Europaea (2020)The scientific objective of the conference is twofold. First, several experts in the field of dispersive and wave equations will present their recent advances. A second objective is to propose some conferences in analysis beyond the field of dispersive PDEs. The Scientific Committee hopes that all talks will be accessible to a general audience in analysis.Scientific Committee: M. Dafermos, A.-L. Dalibard, H. Duminil-Copin, T. Duyckaerts, E. Hebey, Y. Martel, G. Ponce, P. Raphaël, L. Saint-Raymond et H. ZaagOrganising Committee: C. Collot, R. Côte, F. Demengel, T. Duyckaerts, J. Jendrej, Y. Lan, E. Logak, Y. Martel, C. Muñoz, P. Raphaël, J. Szeftel, N. Tzvetkov et H. ZaagInvited Speakers:Henri Berestycki, EHESSNicolas Burq, Université de Paris-SaclaySimon Brendle, Columbia UniversityMaria Colombo, EPFLCamillo De Lellis, IASThierry Giamarchi, Université de GenèveFrançois Golse, École polytechniqueOana Ivanovici, CNRS & Sorbonne UniversitéCarlos Kenig, University of ChicagoSergiu Klainerman, Princeton UniversityPierre-Louis Lions, Collège de FranceNader Masmoudi, NYUHiroshi Matano, Meiji UniversityAndrea Nahmod, University of MassachusettsFelix Otto, Max-Planck Institut fur MathematikPierre Raphaël, University of CambridgeIgor Rodnianski, Princeton UniversityWilhelm Schlag, Yale UniversitySylvia Serfaty, NYUDaniel Tataru, UC BerkeleyLuis Vega, BCAMSijue Wu, University of MichiganThis event will be held at IHES, Bures-sur-Yvette, and at CY Advanced Studies, and is open to all.Registration is free and open until April 21, 2022.

The aim of this workshop is to bring together mathematicians and computer scientists around some talks on recent results from statistics, machine learning, and more generally data science research. Various topics in machine learning, optimization, deep learning, optimal transport, inverse problems, statistics, and problems of scientific reproducibility will be presented. This workshop is particularly intended for doctoral and post-doctoral researchers.Registration is free and open until March 1, 2023.Organizers: Gilles Blanchard (LMO/Université Paris-Saclay)Florence Tupin (LTCI/Télécom Paris)Invited speakers:Isabelle Bloch (LIP6/Sorbonne Université – LTCI/Télécom Paris)Antoine Cornuéjols (MIA/AgroParisTech)Aymeric Dieuleveut (CMAP/École polytechnique)Elisabeth Gassiat (LMO/Université Paris-Saclay)Mohammed Nabil El Korso (L2S/CentraleSupélec)Mathilde Mougeot (ENSIIE & Centre Borelli/ENS Paris-Saclay)

Le théorème de comparaison est un sujet classique en théorie de Hodge p-adique. Récemment, Guo et Reinecke ont montré un théorème de comparaison p-adique pour les systèmes locaux cristallins en utilisant la théorie de cohomologie prismatique de Bhatt-Scholze. Un des points clés de leur travail est d’établir un théorème de comparaison étale-prismatique pour les systèmes locaux cristallins. Dans cet exposé, j’expliquerai une nouvelle approche à la comparaison étale-prismatique, qui marche bien aussi dans le cas semi-stable.   Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: « subscribe seminaire_mathematique PRENOM NOM »(indiquez vos propres prénom et nom) et laissez le corps du message vide. 

Nash’s geometric ideas in PDE have returned to the prominence due to their role in the solution of Onsager’s conjecture on energy conservation in the Euler equation and counterexamples to regularity of non-linear elliptic equations.The first lecture will contain an elementary introduction to the basic geometric techniques and results starting from a short geometric proof of the C1-isometric immersion and related theorems.The second lecture will survey more recent results, ideas and techniques. Veuillez cliquer sur le lien ci-dessous afin de rejoindre le webinaire : https://us02web.zoom.us/j/81163611896?pwd=T043TzNvZnpUbUNiSE1BM0FBa05RQT09 Code secret : 822885 Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: « subscribe seminaire_mathematique PRENOM NOM »(indiquez vos propres prénom et nom) et laissez le corps du message vide. 

Nash’s geometric ideas in PDE have returned to the prominence due to their role in the solution of Onsager’s conjecture on energy conservation in the Euler equation and counterexamples to regularity of non-linear elliptic equations.The first lecture will contain an elementary introduction to the basic geometric techniques and results starting from a short geometric proof of the C1-isometric immersion and related theorems.The second lecture will survey more recent results, ideas and techniques. Veuillez cliquer sur le lien ci-dessous afin de rejoindre le webinaire : https://us02web.zoom.us/j/81163611896?pwd=T043TzNvZnpUbUNiSE1BM0FBa05RQT09 Code secret : 822885 Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: « subscribe seminaire_mathematique PRENOM NOM »(indiquez vos propres prénom et nom) et laissez le corps du message vide. 

The frame flow over negatively-curved Riemannian manifolds is a historical example of a partially hyperbolic dynamical system. Excluding some obvious counterexamples such as Kähler manifolds, its ergodicity was conjectured by Brin in the 70s. While it has been known since Brin-Gromov (1980) that it is ergodic on odd-dimensional manifolds (and dimension not equal to 7), the even-dimensional case is still open. In this talk, I will explain recent progress towards this conjecture: I will show that in dimensions 4k+2 the frame flow is ergodic if the Riemannian manifold is 0.27 pinched (i.e., the sectional curvature is between -1 and -0.27), and in dimensions 4k if it is 0.55 pinched. This problem turns out to be surprisingly rich and at the interplay of different fields: (partially) hyperbolic dynamical systems, algebraic topology (classification of topological structures over spheres), Riemannian geometry and harmonic analysis (Pestov identity and microlocal analysis). Joint work with Mihajlo Cekić, Andrei Moroianu, Uwe Semmelmann.

Classical mapping class groups, i.e. for surfaces of finite type, are well-studied but they are not particularly interesting from the point of view of topological groups as they are discrete.When we turn our attention to surfaces of infinite type, the situation changes drastically: In particular, the mapping class groups are now « big » (here: uncountable) and we can define an interesting (here: non-discrete) topology on them. In particular, big mapping class groups are Polish groups and we can ask many new questions such as on automatic continuity or their (large-scale) geometry.In this talk, I will give an introduction to surfaces of infinite type and big mapping class groups and then focus on the question of topological behaviour of conjugacy classes. The second part is based on joint work with Jesús Hernández Hernández, Michael Hrušák, Israel Morales, Manuel Sedano, and Ferrán Valdez, and will feature tools from model theory in the proofs.

Probability and analysis informal seminarThe goal of this informal lecture series is to explain the analysis/PDE point of view of some problems which arise in statistical physics and probability. I will try to argue that the language of elliptic/parabolic homogenization brings a new perspective to a wide range of problems, and that the quantitative « coarse-graining » methods are surprisingly useful and adaptable. We will try to cover the first part of the recent monograph co-written with Tuomo Kuusi (available here: https://arxiv.org/abs/2210.06488), and then proceed based on the interests of the audience.  ========Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: « subscribe seminaire_mathematique PRENOM NOM »(indiquez vos propres prénom et nom) et laissez le corps du message vide.

Probability and analysis informal seminarThe goal of this informal lecture series is to explain the analysis/PDE point of view of some problems which arise in statistical physics and probability. I will try to argue that the language of elliptic/parabolic homogenization brings a new perspective to a wide range of problems, and that the quantitative « coarse-graining » methods are surprisingly useful and adaptable. We will try to cover the first part of the recent monograph co-written with Tuomo Kuusi (available here: https://arxiv.org/abs/2210.06488), and then proceed based on the interests of the audience.  ========Pour être informé des prochains séminaires vous pouvez vous abonner à la liste de diffusion en écrivant un mail à sympa@listes.math.cnrs.fr avec comme sujet: « subscribe seminaire_mathematique PRENOM NOM »(indiquez vos propres prénom et nom) et laissez le corps du message vide.