Vous trouverez ci-dessous le planning du séminaire d’Analyse
Fonctionnelle pour l’année 2016-2017. Le programme de l’année en cours se trouve
ici.
Pour contacter la responsable (Yulia Kuznetsova) : yulia.kuznetsova univ-fcomte.fr.
Pour s’abonner au séminaire : ACM.
-Mercredi 3 mai à 11h00: Gilles Pisier, IMJ.
-Mardi 30 mai: Jean Roydor, Bordeaux.
Avril
Sawyer's conjecture : history and beyond
In this talk, I will introduce the Sawyer's conjecture, which was proposed by Sawyer in 1980s. Then in 2005, Cruz-Uribe, Martell and Pérez finally solved this conjecture, they also proposed a new conjecture, which can be viewed as the most singular case of several extensions of Sawyer's conjecture. I will give a positive answer to the new conjecture. Several quantitative estimates are also obtained. This work is jointly with Sheldy Ombrosi and Carlos Pérez.
-Mardi 11 avril: Marat Aukhadiev, Münster.
C*-algebras of left cancellative semigroups. Inverse semigroup approach.
We will discuss the new approach to the definition of the C*-algebra of a left cancellative semigroup. We will see how it resolves the problems of the old construction. Some benefits of this new approach, such as amenability vs. nuclearity, crossed products, connections with partial crossed products, will also be decribed.
Mars
-Mardi 7 mars: Runlian Xia, Besancon.
TBA
-Mardi 14 mars: Robert Yuncken, Clermont-Ferrand.
TBA
-Mardi 21 mars: Malte Gerhold, Greifswald.
New examples of generalized Brownian motions
-Mardi 28 mars: Leonard Cadilhac, Caen.
TBA
Février
Normes équivalentes avec la propriété $(\beta )$ de Rolewicz et applications
-Mardi 21 février: Relâche, .
Vacances d'hiver
-Mardi 28 février: Elizabeth Strouse, Bordeaux.
Truncated Toeplitz operators
-Mardi 7 février: Un Cig Ji, .
Anticipating Quantum Stochastic Integrals
Janvier
Schur properties over some Lipschitz-free spaces.
It has been known that the free spaces of countable compacts enjoy the Schur property. In this talk we will show that these (and other) spaces in fact satisfy a stronger property, the so called 1-Schur property. Also, we are going to show that $F(\ell _p)$ enjoys the (usual) Schur property whenever $p<1$. This establishes the first example of $F(M)$ with Schur property when $M$ is neither countable, nor snowflaking of another metric space.
-Mardi 17 janvier: Relâche, Trop d'absents.
-Mardi 24 janvier: Quanhua Xu, UFC.
La théorie vectorielle de Littlewood-Paley-Stein revisitée.
-Mardi 31 janvier: Relâche, École de Barboux.
Décembre
On quantum increasing sequences.
Quantum increasing sequences were introduced by S. Curran to characterize free conditional independence by means of comparing joint distributions of initial segments of a sequence of random variables to joint distributions of initial segments of a subsequence of that sequence of random variables, à la Ryll-Nardzewski. This is a de Finetti type theorem, but with weakened assumptions. I will explain the rôle of increasing sequences in free probability and discuss some results of mine in the theory of compact quantum groups, that grew out of the study of the connection of quantum increasing sequences and quantum permutations.
-Mardi 13 décembre: Aris Daniilidis, Université du Chili.
De la dynamique du gradient au processus de rafle
Le processus de rafle a été introduit par Jean-Jacques Moreau dans les années 70 pour modéliser certaines problèmes de la mécanique non-régulière. On établit une variante de la technique de desingularisation de Kurdyka pour desingulariser les co-dérivées du processus de rafle dans le cas définissable, et garantir ainsi la finitude de longueur de ses orbites. Ce résultat, dans le cas particulier où le processus de rafle correspond aux sous-niveaux d'une fonction (non nécessairement régulière), généralise les résultats connus pour les orbites des systèmes dynamiques de type sous-gradient.
Novembre
Multiple quantum Wiener integrals
-Mardi 8 novembre: Ignacio Vergara, ENS Lyon.
La propriété $p$-AP pour le groupe SL(3,R)
La $p$-AP est une propriété d’approximation pour les groupes localement compacts. On peut la voir comme une “version $L^p$” de la AP de Haagerup et Kraus. Je commencerai par définir cette propriété et en suite j’expliquerai comment on peut montrer que le groupe SL(3,R) ne satisfait pas $p$-AP pour aucun 1< p <$\infty$.
-Jeudi 17 novembre, 13h45: Serguei Kisliakov, Steklov Mathematical Institute, Saint-Pétersbourg.
Certains nouvelles estimations dans le théorème de la couronne.
-Mardi 22 novembre 13h30: Sebastien Schleissinger, Université de Wuerzburg.
The Loewner Equation and Monotone Probability Theory
The Loewner differential equation is an important tool in geometric function theory. It has been introduced by C. Loewner in 1923 in order to attack the Bieberbach conjecture (proven by L. de Branges in 1985). In 2000, O. Schramm considered a stochastic version of this equation, which turned out to have striking applications, in particular in statistical physics and conformal field theory. Schramm’s equation has become a field which is now called Schramm-Loewner Evolution (SLE). In this talk we consider a simple relation of Loewner theory to monotone probability theory. Certain Loewner equations can be interpreted as evolution equations for quantum processes.
-Mardi 22 novembre, 14h45: Hun Hee Lee, Seoul National University.
Similarity degree of Fourier algebras
In this talk we will focus on the Dixmier type of similarity question for Fourier algebras and their similarity degrees by Pisier. We will explain that for a locally compact group $G$, amongst a class which contains amenable and small invariant neighbourhood groups (especially discrete groups), that its Fourier algebra $A(G)$ satisfies a completely bounded version of Pisier's similarity property with similarity degree at most 2. Specifically, any completely bounded homomorphism $\pi:A(G)\to B(H)$ admits an invertible $S$ in $B(H)$ for which $\|S\|\|S^{-1}\|\leq \|\pi\|^2_{cb}$ and $S^{-1}\pi(\cdot)S$ extends to a $*$-representation of the C*-algebra $C_0(G)$.
-Mardi 29 novembre: Gilles Godefroy, Université Paris 6.
The complexity of the isomorphism class of some Banach spaces
Octobre
Plongements grossièrement Lipschitz entre espaces de James
Il est connu que $\ell_q$ ne se plonge pas grossièrement Lipschitz dans $\ell_p$ pour $q\neq p$ ($p, q \geq 1$). On essaie d’adapter les méthodes utilisées alors au cas des espaces de James.
-Mardi 11 octobre: relâche, Journées GDR, Toulouse.
-Mardi 18 octobre: Sergey Tikhonov , CRM, Barcelona.
Measures of smoothness and Fourier transforms
In this talk we discuss some recent results related to the quantitative Riemann-Lebesgue lemma on relationship between behavior of the Fourier transform at infinity and smoothness of a function.
-Mardi 25 octobre: Hubert Klaja, École Centrale de Lille.
Image numérique et calcul fonctionnel
Si $T$ est un opérateur linéaire borné, alors pour tout polynôme $p$, le spectre de $p(T)$ verifie $\sigma(p(T)) = p(\sigma(T))$. Ce n'est plus vrai si l'on remplace le spectre par l'image numérique. Dans cet exposé on discutera d'une nouvelle preuve d'un résultat de Drury qui permet de localiser l'image numérique de $p(T)$. C'est un travail en collaboration avec Javad Mashreghi et Thomas Ransford.
Septembre
-Mardi 13 septembre: Marek Cúth, Université Charles, Prague.
Embedding of ℓ1 into Lipschitz-free Banach spaces and ℓ∞ into their duals
Given a metric space M, it is possible to construct a Banach space ℱ(M) in such a way that the Lipschitz structure of M corresponds to the linear structure of ℱ(M). This space ℱ(M) is sometimes called the "Lipschitz-free space over M". The study of Lipschitz-free Banach spaces became an active field of study. I will present our recent result with M. Johanis that ℓ∞ embeds isometrically into the dual of every infinite-dimensional Lipschitz-free Banach space and that it is often the case that a Lipschitz-free Banach space contains a 1-complemented subspace isometric to ℓ1. We do not know whether the later is true for every infinite-dimensional Lipschitz-free Banach space.
-Mardi 20 septembre: Safoura Jafar-Zadeh , UFC.
Isometric isomorphisms of the annihilator of $C_0(G)$ in $LUC(G)^*$
For a locally compact group $G$, let $C_b(G)$ be the space of all complex-valued, continuous and bounded functions on $G$ equipped with the sup-norm, and $LUC(G)$ be the subspace of $C_b(G)$ consisting of all functions $f$ such that the map $G\to C_b(G);x\mapsto l_xf$ is continuous, where $l_xf$ is the function defined by $l_xf(y)=f(xy)$, for each $y\in G.$ In this talk, I will show that if $G$ is a locally compact group and $H$ is a discrete group then whenever there exists a weak-star continuous isometric isomorphism between $C_0(G)^\perp$ (the annihilator of $C_0(G)$ in $LUC(G)^*$) and $C_0(H)^\perp$, then $G$ is isomorphic to $H$ as a topological group. Several related results will also be discussed.
-Mardi 27 septembre: Uwe Franz, UFC.
HUNT FORMULA FOR SUq(n) AND Uq(n)
Joint work with Anna Kula, Martin Lindsay, and Michael Skeide. We provide a Hunt type formula for the infinitesimal generators of Lévy process on the compact quantum groups SUq(N )and Uq(N ). In particular, we obtain a decomposition of such generators into a gaussian part and a "jump" type part, similar to the classical Hunt formula.