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Bibliographic Details
Main Author: Morando, Basile
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2407.11738
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author Morando, Basile
author_facet Morando, Basile
contents We show that, given a continuous action $α$ of a locally compact group $G$ on a factor $M$, the relative commutant $M'\cap(M\rtimes_α G)$ is contained in $M\rtimes_α H$ where $H$ is the subgroup of elements acting without spectral gap. As a corollary, we answer a question of Marrakchi and Vaes by showing that if $M$ is semifinite and $α_g$ is not approximately inner for all $g\neq 1$, then $M'\cap (M\rtimes_α G)=\mathbb{C}$.
format Preprint
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institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Strictly outer actions of locally compact groups: beyond the full factor case
Morando, Basile
Operator Algebras
We show that, given a continuous action $α$ of a locally compact group $G$ on a factor $M$, the relative commutant $M'\cap(M\rtimes_α G)$ is contained in $M\rtimes_α H$ where $H$ is the subgroup of elements acting without spectral gap. As a corollary, we answer a question of Marrakchi and Vaes by showing that if $M$ is semifinite and $α_g$ is not approximately inner for all $g\neq 1$, then $M'\cap (M\rtimes_α G)=\mathbb{C}$.
title Strictly outer actions of locally compact groups: beyond the full factor case
topic Operator Algebras
url https://arxiv.org/abs/2407.11738