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Date
Editeur
Auteur
Titre
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Semyon Dyatlov - Spectral gaps for normally hyperbolic trapping
/ Fanny Bastien
/ 30-06-2014
/ Canal-u.fr
Dyatlov Semyon
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Voir le résumé
Motivated by wave decay for Kerr and Kerr de Sitter black holes, we study spectral gaps for codimension 2 normally hyperbolic trapped sets with smooth stable/unstable foliations. Using semiclassical defect measures, we recover the gap of Wunsch Zworski and Nonnenmacher Zworski in our case. Under the stronger assumptions of r normal hyperbolicity and pinching, we discover further spectral gaps, meaning that resonances are stratified into bands by decay rates. Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, General Relativity, institut fourier, summer school, asymptotic analysis
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Franc Forstnerič - Non singular holomorphic foliations on Stein manifolds (Part 1)
/ Fanny Bastien
/ 19-06-2012
/ Canal-u.fr
Forstnerič Franc
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Voir le résumé
A nonsingular holomorphic foliation of codimension on a complex manifold is locally given by the level sets of a holomorphic submersion to the Euclidean space . If
is a Stein manifold, there also exist plenty of global foliations of
this form, so long as there are no topological obstructions. More
precisely, if then any -tuple of pointwise linearly independent (1,0)-forms can be continuously deformed to a -tuple of differentials where is a holomorphic submersion of to . Such a submersion always exists if is no more than the integer part of . More generally, if is a complex vector subbundle of the tangent bundle such that is a flat bundle, then is homotopic (through complex vector subbundles of ) to an integrable subbundle, i.e., to the tangent bundle of a nonsingular holomorphic foliation on .
I will prove these results and discuss open problems, the most
interesting one of them being related to a conjecture of Bogomolov. Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, courbes, institut fourier, summer school, feuilletages, holomorphic foliations
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Christiane Frougny - Systèmes de numération et automates (Part 1)
/ Fanny Bastien
/ 27-06-2013
/ Canal-u.fr
Frougny Christiane
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Voir le résumé
Automates
finis et langages rationnels de mots finis • Automates finis et mots
infinis • Systèmes de numération à base réelle • Nombres de Pisot,
nombres de Parry et nombres de Perron • Systèmes de numération définis
par une suite Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, dynamics, institut fourier, summer school, number theory, automates, Systèmes de numération
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Joseph Fu - Integral geometric regularity (Part 1)
/ Fanny Bastien
/ 22-06-2015
/ Canal-u.fr
Fu Joseph
Voir le résumé
Voir le résumé
In the original form given by Blaschke
in the 1930s, the famous Principal Kinematic Formula expresses the Euler
characteristic of the intersection of two sufficiently regular objects
in euclidean space, integrated over the space of all possible relative
positions, in terms of geometric invariants associated to each of them
individually. It is natural to wonder about the precise regularity
needed for this to work. The question turns on the existence of the
normal cycle of such an object A, i.e. an integral current that stands
in for its manifolds of unit normals if A is too irregular for the
latter to exist in a literal sense. Despite significant recent progress,
a comprehensive understanding of this construction remains maddeningly
elusive. In these lectures we will discuss both of these aspects. Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, institut fourier, summer school, geometric measure theory, calculus of variation
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Joseph Fu - Integral geometric regularity (Part 2)
/ Fanny Bastien
/ 23-06-2015
/ Canal-u.fr
Fu Joseph
Voir le résumé
Voir le résumé
In the original form given by Blaschke
in the 1930s, the famous Principal Kinematic Formula expresses the Euler
characteristic of the intersection of two sufficiently regular objects
in euclidean space, integrated over the space of all possible relative
positions, in terms of geometric invariants associated to each of them
individually. It is natural to wonder about the precise regularity
needed for this to work. The question turns on the existence of the
normal cycle of such an object A, i.e. an integral current that stands
in for its manifolds of unit normals if A is too irregular for the
latter to exist in a literal sense. Despite significant recent progress,
a comprehensive understanding of this construction remains maddeningly
elusive. In these lectures we will discuss both of these aspects. Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, institut fourier, summer school, geometric measure theory, calculus of variation
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Joseph Fu - Integral geometric regularity (Part 3)
/ Fanny Bastien
/ 24-06-2015
/ Canal-u.fr
Fu Joseph
Voir le résumé
Voir le résumé
In the original form given by Blaschke
in the 1930s, the famous Principal Kinematic Formula expresses the Euler
characteristic of the intersection of two sufficiently regular objects
in euclidean space, integrated over the space of all possible relative
positions, in terms of geometric invariants associated to each of them
individually. It is natural to wonder about the precise regularity
needed for this to work. The question turns on the existence of the
normal cycle of such an object A, i.e. an integral current that stands
in for its manifolds of unit normals if A is too irregular for the
latter to exist in a literal sense. Despite significant recent progress,
a comprehensive understanding of this construction remains maddeningly
elusive. In these lectures we will discuss both of these aspects. Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, institut fourier, summer school, geometric measure theory, calculus of variation
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Joseph Fu - Integral geometric regularity (Part 4)
/ Fanny Bastien
/ 24-06-2015
/ Canal-u.fr
Fu Joseph
Voir le résumé
Voir le résumé
In the original form given by Blaschke
in the 1930s, the famous Principal Kinematic Formula expresses the Euler
characteristic of the intersection of two sufficiently regular objects
in euclidean space, integrated over the space of all possible relative
positions, in terms of geometric invariants associated to each of them
individually. It is natural to wonder about the precise regularity
needed for this to work. The question turns on the existence of the
normal cycle of such an object A, i.e. an integral current that stands
in for its manifolds of unit normals if A is too irregular for the
latter to exist in a literal sense. Despite significant recent progress,
a comprehensive understanding of this construction remains maddeningly
elusive. In these lectures we will discuss both of these aspects. Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, institut fourier, summer school, geometric measure theory, calculus of variation
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Joseph Fu - Integral geometric regularity (Part 5)
/ Fanny Bastien
/ 24-06-2015
/ Canal-u.fr
Fu Joseph
Voir le résumé
Voir le résumé
In the original form given by Blaschke
in the 1930s, the famous Principal Kinematic Formula expresses the Euler
characteristic of the intersection of two sufficiently regular objects
in euclidean space, integrated over the space of all possible relative
positions, in terms of geometric invariants associated to each of them
individually. It is natural to wonder about the precise regularity
needed for this to work. The question turns on the existence of the
normal cycle of such an object A, i.e. an integral current that stands
in for its manifolds of unit normals if A is too irregular for the
latter to exist in a literal sense. Despite significant recent progress,
a comprehensive understanding of this construction remains maddeningly
elusive. In these lectures we will discuss both of these aspects. Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, institut fourier, summer school, geometric measure theory, calculus of variation
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Christian Gérard - Introduction to field theory on curved spacetimes (Part 1)
/ Fanny Bastien
/ 20-06-2014
/ Canal-u.fr
Gérard Christian
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Voir le résumé
The aim of these lectures is to give an introduction to quantum field theory on curved spacetimes, from the point of view of partial differential equations and microlocal analysis. I will concentrate on free fields and quasi-free states, and say very little on interacting fields or perturbative renormalization. I will start by describing the necessary algebraic background, namely CCR and CAR algebras, and the notion of quasi-free states, with their basic properties and characterizations. I will then introduce the notion of globally hyperbolic spacetimes, and its importance for classical field theory (advanced and retarded fundamental solutions, unique solvability of the Cauchy problem). Using these results I will explain the algebraic quantization of the two main examples of quantum fields ona manifold, namely the Klein-Gordon (bosonic) and Dirac (fermionic) fields.In the second part of the lectures I will discuss the important notion of Hadamardstates , which are substitutes in curved spacetimes for the vacuum state in Minkowskispacetime. I will explain its original motivation, related to the definition of therenormalized stress-energy tensor in a quantum field theory. I will then describethe modern characterization of Hadamard states, by the wavefront set of their twopointfunctions, and prove the famous Radzikowski theorem , using the Duistermaat-Hörmander notion of distinguished parametrices . If time allows, I will also describe the quantization of gauge fields, using as example the Maxwell field. Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, General Relativity, institut fourier, summer school, asymptotic analysis
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Alessandro Giacomini - Free discontinuity problems and Robin boundary conditions
/ 30-06-2015
/ Canal-u.fr
Giacomini Alessandro
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Voir le résumé
indisponible Mot(s) clés libre(s) : mathématiques, Grenoble, école d'été, institut fourier, summer school, geometric measure theory, calculus of variation
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