Group von Neumann algebras, inner amenability, and unit groups of continuous rings

Fuente: arXiv
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Main Author: Schneider, Friedrich Martin
Format: Preprint
Published: 2022
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author Schneider, Friedrich Martin
author_facet Schneider, Friedrich Martin
contents We prove that, if a discrete group $G$ is not inner amenable, then the unit group of the ring of operators affiliated with the group von Neumann algebra of $G$ is non-amenable with respect to the topology generated by its rank metric. This provides examples of non-discrete irreducible, continuous rings (in von Neumann's sense) whose unit groups are non-amenable with regard to the rank topology. Our argument establishes and uses connections with Eymard--Greenleaf amenability of the action of the unitary group of a $\mathrm{II}_{1}$ factor on the associated space of projections of a fixed trace.
format Preprint
id arxiv_https___arxiv_org_abs_2211_03537
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Group von Neumann algebras, inner amenability, and unit groups of continuous rings
Schneider, Friedrich Martin
Operator Algebras
Functional Analysis
Group Theory
43A07, 22D25, 06C20, 16E50
We prove that, if a discrete group $G$ is not inner amenable, then the unit group of the ring of operators affiliated with the group von Neumann algebra of $G$ is non-amenable with respect to the topology generated by its rank metric. This provides examples of non-discrete irreducible, continuous rings (in von Neumann's sense) whose unit groups are non-amenable with regard to the rank topology. Our argument establishes and uses connections with Eymard--Greenleaf amenability of the action of the unitary group of a $\mathrm{II}_{1}$ factor on the associated space of projections of a fixed trace.
title Group von Neumann algebras, inner amenability, and unit groups of continuous rings
topic Operator Algebras
Functional Analysis
Group Theory
43A07, 22D25, 06C20, 16E50
url https://arxiv.org/abs/2211.03537