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Nombre de programmes trouvés : 2707
Conférences

le (57m31s)

R. Monti - Excess and tangents of sub-Riemannian geodesics

We present some recent results on the regularity problem of sub-Riemannian length minimizing curves. This is a joint work with A. Pigati and D. Vittone. After introducing the notion of excess for a horizontal curve, we show that at any point of a length minimizing curve excess is infinitesimal at some sequence of scales. This implies the existence of a linear tangent. We also discuss other results related to excess.
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Conférences

le (57m9s)

Maciej Zworski - Fractal uncertainty for transfer operators

I will present a new explanation of the connection between the fractal uncertainty principle (FUP) of Bourgain-Dyatlov, a statement in harmonic analysis, and the existence of zero free strips for Selberg zeta functions, which is a statement in geometric scattering/dynamical systems. The connection is proved using (relatively) elementary methods via the Ruelle transfer operator which is a well known object in thermodynamical formalism of chaotic dynamics. The talk will assume no knowledge of the subject and I will also present applications of FUP to properties ...
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Conférences

le (59m37s)

Giuseppe Buttazzo - One dimensional optimal reinforcements of elastic structures

In this talk we study the optimal reinforcement of an elastic membrane, fixed at its boundary, by means of a connected one-dimensional structure. We show the existence of an optimal solution that may present multiplicities, that is regions where the optimal structure overlaps. Some numerical simulations are shown to confirm this issue and to illustrate the complexity of the optimal structures when their total length becomes large.
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Conférences

le (54m35s)

Patrick Dehornoy - La théorie des ensembles cinquante ans après Cohen

On présentera quelques résultats de théorie des ensembles récents, avec un accent sur l'hypothèse du continu et la possibilité de résoudre la question après les résultats négatifs bien connus de Gödel et Cohen, et sur les tables de Laver, qui sont des structures finies explicites, dont certaines propriétés combinatoires simples n'ont été établies jusqu'à présent que grâce à des axiomes de grand cardinal (non démontrables), une situation très paradoxale.
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Conférences

le (58m58s)

Patricia Bouret - Erreurs et Tests statistiques

Un test statistique  est un outil très puissant pour prendre des décisions, cependant ils sont parfois très mal interprétés. Après une petite introduction historique qui montrera que les débats autour de ces notions remontent à Fisher, je me focaliserai sur les tests multiples et j'introduirai les différents types d'erreur, celles qui sont faciles à contrôler (Type 1) et celles qui sont plus difficiles à appréhender (Type 2) que nous reformulons en terme de vitesses de séparation.
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Cours magistraux

le (59m19s)

J. Aramayona - MCG and infinite MCG (Part 1)

The first part of the course will be devoted to some of the classical results about mapping class groups of finite-type surfaces. Topics may include: generation by twists, Nielsen-Thurston classification, abelianization, isomorphic rigidity, geometry of combinatorial models. In the second part we will explore some aspects of "big" mapping class groups, highlighting the analogies and differences with their finite-type counterparts, notably around isomorphic rigidity, abelianization, and geometry of combinatorial models.
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Cours magistraux

le (1h1m4s)

B. Deroin - Monodromy of algebraic families of curves (Part 1)

The mini-course will focus on the properties of the monodromies of algebraic families of curves defined over the complex numbers. One of the goal will be to prove the irreducibility of those representations for locally varying families (Shiga). If time permit we will see how to apply this to prove the geometric Shafarevich and Mordell conjecture. The material that will be developed along the lectures are - analytic structure of Teichmüller spaces - theory of Kleinian groups - Bers embedding - b-groups - Mumford compactness criterion - Imayoshi-Shiga finiteness theorem.
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Cours magistraux

le (1h11m15s)

B. Deroin - Monodromy of algebraic families of curves (Part 3)

The mini-course will focus on the properties of the monodromies of algebraic families of curves defined over the complex numbers. One of the goal will be to prove the irreducibility of those representations for locally varying families (Shiga). If time permit we will see how to apply this to prove the geometric Shafarevich and Mordell conjecture. The material that will be developed along the lectures are - analytic structure of Teichmüller spaces - theory of Kleinian groups - Bers embedding - b-groups - Mumford compactness criterion - Imayoshi-Shiga finiteness theorem.
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