An example of an infinite amenable group with the ISR property

Fuente: arXiv
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Main Authors: Jiang, Yongle, Zhou, Xiaoyan
Format: Preprint
Published: 2023
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author Jiang, Yongle
Zhou, Xiaoyan
author_facet Jiang, Yongle
Zhou, Xiaoyan
contents Let $G$ be $S_{\mathbb{N}}$, the finitary permutation (i.e. permutations with finite support) group on positive integers $\mathbb{N}$. We prove that $G$ has the invariant von Neumann subalgebras rigidity (ISR, for short) property as introduced in Amrutam-Jiang's work. More precisely, every $G$-invariant von Neumann subalgebra $P\subseteq L(G)$ is of the form $L(H)$ for some normal sugbroup $H\lhd G$ and in this case, $H=\{e\}, A_{\mathbb{N}}$ or $G$, where $A_{\mathbb{N}}$ denotes the finitary alternating group on $\mathbb{N}$, i.e. the subgroup of all even permutations in $S_{\mathbb{N}}$. This gives the first known example of an infinite amenable group with the ISR property.
format Preprint
id arxiv_https___arxiv_org_abs_2312_08061
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle An example of an infinite amenable group with the ISR property
Jiang, Yongle
Zhou, Xiaoyan
Operator Algebras
Let $G$ be $S_{\mathbb{N}}$, the finitary permutation (i.e. permutations with finite support) group on positive integers $\mathbb{N}$. We prove that $G$ has the invariant von Neumann subalgebras rigidity (ISR, for short) property as introduced in Amrutam-Jiang's work. More precisely, every $G$-invariant von Neumann subalgebra $P\subseteq L(G)$ is of the form $L(H)$ for some normal sugbroup $H\lhd G$ and in this case, $H=\{e\}, A_{\mathbb{N}}$ or $G$, where $A_{\mathbb{N}}$ denotes the finitary alternating group on $\mathbb{N}$, i.e. the subgroup of all even permutations in $S_{\mathbb{N}}$. This gives the first known example of an infinite amenable group with the ISR property.
title An example of an infinite amenable group with the ISR property
topic Operator Algebras
url https://arxiv.org/abs/2312.08061