13 juin 2019

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Programme : La conférence aura lieu à l’amphithéâtre J.C. Yoccoz, Institut de Mathématiques, Université de Paris Saclay, du 12 au 14 juin.
Voir le site https://grossmann-meyer.sciencescon...
Alexandre Grossmann et Yves Meyer ont contribué aux fondements de la théorie des ondelettes et à leurs applications. Cette conférence célèbrera leurs travaux de recherche sur les ondelettes et, plus largement, les multiples domaines scientifiques qu’ils ont explorés : physique théorique, analyse harmonique, traitement du signal et de l’image, sciences de l’univers, géophysique, biologie mathématique. Elle rendra un hommage scientifique et amical à la mémoire d’Alexandre Grossmann, qui nous a quittés le 12 Février 2019.

 

Jing Tao (University of Oklahoma)
Thick surfaces and the diameter of moduli space

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Lieu : IMO, salle 2L8

Résumé : Let M_g be the moduli space of hyperbolic surfaces of genus g. The thick part of M_g is set the surfaces with a lower bound on the length of the shortest curve. The thick part is compact, and hence has finite diameter with respect to any metric endowed on M_g. In joint work with Kasra Rafi, we showed that, with respect to the Teichmuller or Thurston metric, the diameter of the thick part has order log(g). In this talk, I will explain how to construct pairs of surfaces that realize this diameter. There are essentially two reasons for surfaces to be far way from each other : combinatorial and geometric. I will explain what these two notions are and construct four interesting examples of hyperbolic surfaces. Three of these examples will be constructed using trivalent graphs, and the fourth will be a variation of Buser’s hairy torus.

Notes de dernières minutes : L’exposé sera précédé d’un café culturel assuré à 13h par Camille Horbez.

Thick surfaces and the diameter of moduli space  Version PDF

Mitia Duerinckx (ENS de Lyon)
Fluctuations in stochastic homogenization

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Lieu : IMO, Salle 3L8

Résumé : In this talk, we review recent developments on large-scale fluctuations of the solution operator for a uniformly elliptic PDE in divergence form with random coefficients. We focus for simplicity on Gaussian-type coefficients and make strong use of Malliavin calculus. We establish a general pathwise theory of fluctuations based on the new key notion of homogenization commutator. We further investigate the effect of strongly correlated coefficients, study possible degeneracy issues for the limit, and show how the theory can be extended to optimally describe higher-order fluctuations in terms of suitable higher-order commutators.

Fluctuations in stochastic homogenization  Version PDF