M.
Petru Mironescu
(Institut Camille Jourdan, Lyon 1)
03/04/2017 15:15
The smoothness of a function $f$ is described by the rate of convergence of the smoothings of $f$ to $f$. Another way to measure smoothness is given by the decay properties of the derivatives of these smoothings: this is encoded by the theory of weighted Sobolev spaces, developed in the 60s.
In the first part of the lecture, we will recall some striking results of this theory, with focus on...
Mlle
Cristina Benea
(Universite de Nantes)
03/04/2017 16:30
Dr
Yulia Kuznetsova
(Université de Bourgogne Franche Comté)
03/04/2017 17:30
Let $G$ be a locally compact group, and let $1\le p < \infty$. Consider the weighted $L^p$-space
$L^p(G,\omega)=\{f:\int|f\omega|^p<\infty\}$, where $\omega:G\to \R$ is a
positive measurable function. Under appropriate conditions on $\omega$, $G$ acts on $L^p(G,\omega)$
by translations. When is this action hypercyclic, that is, there is a function in this space such that
the set of all its...
M.
Emmanuel Russ
(Université Grenoble Alpes)
04/04/2017 10:45
Let $d\ge 2$, $\Omega\subset R^d$ be a smooth bounded domain and $f\in L^d(\Omega)$
with $\int_R f(x)dx=0$. Bourgain
and Brezis proved that there exists a vector field $X \in W^{1;d}(\Omega)\cap L^\infty(\Omega)$
such that $div X = f$ and
$||f||_{W^{1;d}}+||f||_{L^\infty}\le C ||f||_{L^d}. $
We will discuss various extensions of this result to more general functions
spaces, and present...
Dr
Benoit Florent Sehba
(University of Ghana)
04/04/2017 14:15
In 1978, D. Békollé and A. Bonami characterized the exact range of weights for which the Bergman projection is bounded on weighted Lebesgue spaces. In 2013, S. Pott and M. C. Reguera found the exact dependence of the norm of the Bergman projection on the Békollé-Bonami characteristic of the weight. In this talk, we discuss extension of these results to the upper-triangle case.
Mlle
Dorothee Frey
(Delft University of Technology)
04/04/2017 15:15
Dr
Marco Vitturi
(Laboratoire Jean Leray, Université de Nantes)
04/04/2017 16:30
Affine measures have been introduced in the past to facilitate the study of Fourier Restriction and the related question of the L^p smoothing properties of averages along submanifolds (convolution Radon transforms). They capture in a geometric way the role of curvature. In this talk we present the Affine Measures and then discuss the geometric interpretation of these objects - a line of...
M.
Karim Kellay
(Univ. Bordeaux)
05/04/2017 10:45
Nous étudions les ensembles d’interpolation, d’unicité et d’échantillonnage multiple pour les espaces de Fock classiques dans
le cas où la multiplicité est non bornée. Nous montrons, dans le cas hilbertien ainsi que celui de la norme uniforme, qu’il
n’y a pas de suites simultanément d’échantillonnage et d’interpolation lorsque la multiplicité tend vers l’infini. Ceci répond
partiellement...
Prof.
Isabelle Chalendar
(UPEM)
05/04/2017 11:45
We study the asymptotic behaviour of the powers $T^n$ of a continuous composition operator $T$ on an arbitrary Banach space $X$ of holomorphic functions on the open unit disc of the complex plane. We show that for composition operators, one has the following dichotomy: either the powers converge uniformly or they do not converge even strongly. We also show that uniform convergence of the...
