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Nombre de programmes trouvés : 888
Séminaires

le (1h5m4s)

Andras Vasy - The Feynman propagator and its positivity properties

One usually considers wave equations as evolution equations, i.e. imposes initial data and solves them. Equivalently, one can consider the forward and backward solution operators for the wave equation; these solve an equation Lu=f" style="position: relative;" tabindex="0" id="MathJax-Element-1-Frame">Lu=f, for say f" style="position: relative;" tabindex="0" id="MathJax-Element-2-Frame">f compactly supported, by demanding that u" style="position: relative;" tabindex="0" id="MathJax-Element-3-Frame">u is supported at points which are reachable by forward, respectively backward, time-like or light-like curves. This property corresponds to causality. But it has been known for a long time that in certain ...
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Cours magistraux

le (1h4m55s)

G. Forni - Cohomological equation and Ruelle resonnences (Part 1)

In these lectures we summarized results on the cohomological equation for translation flows on translation surfaces (myself, Marmi, Moussa and Yoccoz, Marmi and Yoccoz) and apply these results to the asymptotic of correlations for pseudo-Anosov maps, which were recently obtained by a direct method by Faure, Gouezel and Lanneau. In this vein, we consider the generalization of this asymptotic to generic Teichmueller orbits (pseudo-Anosov maps correspond to periodic Teichmueller orbits) and to (partially hyperbolic) automorphisms of Heisenberg nilmanifolds (from results on the cohomological equation due to L. Flaminio and myself).eem
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Séminaires

le (1h4m48s)

Claude Lebrun - Mass, Scalar Curvature, Kähler Geometry, and All That

Given a complete Riemannian manifold that looks enough like Euclidean space at infinity, physicists have defined a quantity called the “mass” that measures the asymptotic deviation of the geometry from the Euclidean model. After first providing a self-contained introduction to the key underlying geometric concepts, I will go on to explain a simple formula, discovered in joint work with Hajo Hein, for the mass of any asymptotically locally Euclidean (ALE) Kähler manifold. When the metric is actually AE (asymptotically Euclidean), our formula ...
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Label UNT Conférences

le (1h4m45s)

Théorie du Contrôle, 50 ans après

La conférence commence par l'introduction de Pierre Bernhard, ancien directeur du centre de recherche Inria à Sophia Antipolis qui présente la carrière d'Alain Bensoussan et met en avant le foisonnement de ses travaux de recherche.En préambule, Alain Besoussant fait la génèse de la création du Centre de l'Inria à Sophia Antipolis.Puis il expose l'évolution de la théorie du contrôle depuis les années 50, qu'il lie, dans une réflexion personnelle avec l'évolution du monde. Ce domaine scientifique qui est né dans le monde déterministe, relativement stable des années 50 jusqu'aux années 1985, a ensuite connu de grandes transformations dans un  contexte ...
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Cours magistraux

le (1h4m44s)

J. Aramayona - MCG and infinite MCG (Part 2)

The first part of the course will be devoted to some of the classicalresults 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 (1h4m38s)

P. Salberger - Quantitative aspects of rational points on algebraic varieties (part1)

Let X be a subvariety of Pn defined over a number field and N(B) be the number of rational points of height at most B on X. There are then general conjectures of Manin on the asymptotic behaviour of N(B) when B goes to infinity. These conjectures can be studied using the Hardy-Littlewood method for non-singular complete intersections of high dimensions and by adelic harmonic analysis for varieties related to algebraic groups. But for most varieties there are no other methods available apart from sieve theory ...
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Conférences

le (1h4m37s)

Antoine Joux - Revisiting discrete logarithms in small/medium characteristic finite fields

In this talk, we present a new algorithm for the computation of discrete logarithms in finite fields of small characteristic. This algorithm combines several previously existing techniques with a few additional ingredients. Among those, the most notable is a new method for generating multiplicative relations with a "systematic side" by composing the polynomial (Xq-X) with homographies. This results in an algorithm of quasi-polynomial complexity for discrete logs in GF(qk) where k is close to q.
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Conférences

le (1h4m35s)

S. Diverio - Kobayashi hyperbolicity of complex projective manifolds and foliations (part 1)

The aim of this mini course is to highlight some links between the study of the Kobayashi hyperbolicity properties of complex projective manifolds and holomorphic foliations. A compact complex space is Kobayashi hyperbolic if and only if every holomorphic map from the complex plane to it is constant. Projective (or more generally compact Kähler) Kobayashi hyperbolic manifolds share many features with projective manifolds of general type, and it is nowadays a classical and important conjecture (due to S. Lang) that a ...
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