Séminaires : Séminaire d'Analyse Fonctionnelle

 Equipe(s) : af, Responsables : E. Abakoumov - D. Cordero-Erausquin - G. Godefroy - O. Guédon - B. Maurey - G.Pisier Email des responsables : Salle : salle 13 - couloir 15-16 - 4ème étage Adresse : Campus Pierre et Marie Curie Description Le Jeudi à 10h30 -  IMJ-PRG - 4 place Jussieu - 75005 PARIS Lien vers les archives des années antérieures à 2015

 Orateur(s) Pavel Mozolyako - Saint Petersburg State University, Titre Weighted Hardy embedding on the bi-tree Date 24/11/2022 Horaire 10:30 à 12:00 Diffusion Résume Let $\Gamma$ be a poly-tree, i.e. a collection of dyadic rectangles on $\mathbb{R}^n$ (Cartesian product of usual dyadic intervals on $\mathbb{R}$) with natural order by inclusion.\\ The Hardy operator and its 'adjoint' are \notag \begin{split} &\mathbf{I}f(R) := \sum_{R\subset Q}f(Q)\\ &\mathbf{I}^*f(Q) := \sum_{R\subset Q}f(R). \end{split} We are investigating the action of this operator  from $L^2(\Gamma,w^{-1})$ to $L^2(\Gamma,\mu)$, or, which is the same, $\mathbf{I}^*$ from $L^2(\Gamma,\mu^{-1})$ to $L^2(\Gamma,w)$, where $w$ and $\mu$ are just collections of non-negative weights attached to the elements of $\Gamma$. If for given $\mu,w$ the Hardy operator is bounded, we call $(\mu,w)$ \textit{the trace measure-weight pair}.\par In this talk we consider a special case -- the dimension $n$ is either 2 or 3 and the weight $w$ is a product weight (a typical case is just $w\equiv 1$). We give a couple of descriptions of such pairs in potential theoretical terms: capacitary and energy conditions. We give a short exposition of two-dimensional results, and discuss problems that arise with increasing the dimension. We also establish a connection to weighted Dirichlet spaces on the polydisc. Salle salle 13 - couloir 15-16 - 4ème étage Adresse Campus Pierre et Marie Curie