The Blum-Hanson property
Type de document :
Article dans une revue scientifique: Article de synthèse/Review paper
DOI :
URL permanente :
Titre :
The Blum-Hanson property
Auteur(s) :
Titre de la revue :
Concrete Operators
Pagination :
92-105
Date de publication :
2019
Discipline(s) HAL :
Mathématiques [math]
Résumé en anglais : [en]
Given a (real or complex, separable) Banach space, and a contraction $T$ on $X$, we say that $T$ \emph{has the Blum-Hanson property} if whenever $x,y \in X$ are such that $T^n x$ tends weakly to $y$ in $X$ as $n$ tends to ...
Lire la suite >Given a (real or complex, separable) Banach space, and a contraction $T$ on $X$, we say that $T$ \emph{has the Blum-Hanson property} if whenever $x,y \in X$ are such that $T^n x$ tends weakly to $y$ in $X$ as $n$ tends to infinity, the means \[\displaystyle \dfrac{1}{N} \sum_{k=1}^N T^{n_k} x \] tend to $y$ in norm for \emph{every} strictly increasing sequence $(n_k)_{k\geq 1}$ of integers.The space $X$ itself has the Blum-Hanson property if every contraction on $X$ has the Blum-Hanson property. We explain the ergodic-theoretic motivation for the Blum-Hanson property, prove that Hilbert spaces have the Blum-Hanson property, and then present a recent criterion of a geometric flavor, due to Lef\`evre-Matheron-Primot, which allows to retrieve essentially all the known examples of spaces with the Blum-Hanson property. Lastly, following Lef\`evre-Matheron, we characterize the compact metric spaces $K$ such that the space $C(K)$ has the Blum-Hanson property.Lire moins >
Lire la suite >Given a (real or complex, separable) Banach space, and a contraction $T$ on $X$, we say that $T$ \emph{has the Blum-Hanson property} if whenever $x,y \in X$ are such that $T^n x$ tends weakly to $y$ in $X$ as $n$ tends to infinity, the means \[\displaystyle \dfrac{1}{N} \sum_{k=1}^N T^{n_k} x \] tend to $y$ in norm for \emph{every} strictly increasing sequence $(n_k)_{k\geq 1}$ of integers.The space $X$ itself has the Blum-Hanson property if every contraction on $X$ has the Blum-Hanson property. We explain the ergodic-theoretic motivation for the Blum-Hanson property, prove that Hilbert spaces have the Blum-Hanson property, and then present a recent criterion of a geometric flavor, due to Lef\`evre-Matheron-Primot, which allows to retrieve essentially all the known examples of spaces with the Blum-Hanson property. Lastly, following Lef\`evre-Matheron, we characterize the compact metric spaces $K$ such that the space $C(K)$ has the Blum-Hanson property.Lire moins >
Langue :
Anglais
Comité de lecture :
Oui
Audience :
Internationale
Vulgarisation :
Non
Projet ANR :
Collections :
Source :
Date de dépôt :
2025-01-24T16:31:04Z
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