Weak*-Simplicity of Convolution Algebras on Discrete Groups

Fuente: arXiv
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Main Author: White, Jared T.
Format: Preprint
Published: 2023
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author White, Jared T.
author_facet White, Jared T.
contents We prove that, given a discrete group $G$, and $1 \leq p < \infty$, the algebra of $p$-convolution operators $CV_p(G)$ is weak*-simple, in the sense of having no non-trivial weak*-closed ideals, if and only if $G$ is an ICC group. This generalises the basic fact that $vN(G)$ is a factor if and only if $G$ is ICC. When $p=1$, $CV_p(G) = \ell^1(G)$. In this case we give a more detailed analysis of the weak*-closed ideals, showing that they can be described in terms of the weak*-closed ideals of $\ell^1(FC(G))$; when $FC(G)$ is finite, this leads to a classification of the weak*-closed ideals of $\ell^1(G)$.
format Preprint
id arxiv_https___arxiv_org_abs_2309_15570
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Weak*-Simplicity of Convolution Algebras on Discrete Groups
White, Jared T.
Functional Analysis
Operator Algebras
43A15, 43A20 (primary), 47L10, 46H10 (secondary)
We prove that, given a discrete group $G$, and $1 \leq p < \infty$, the algebra of $p$-convolution operators $CV_p(G)$ is weak*-simple, in the sense of having no non-trivial weak*-closed ideals, if and only if $G$ is an ICC group. This generalises the basic fact that $vN(G)$ is a factor if and only if $G$ is ICC. When $p=1$, $CV_p(G) = \ell^1(G)$. In this case we give a more detailed analysis of the weak*-closed ideals, showing that they can be described in terms of the weak*-closed ideals of $\ell^1(FC(G))$; when $FC(G)$ is finite, this leads to a classification of the weak*-closed ideals of $\ell^1(G)$.
title Weak*-Simplicity of Convolution Algebras on Discrete Groups
topic Functional Analysis
Operator Algebras
43A15, 43A20 (primary), 47L10, 46H10 (secondary)
url https://arxiv.org/abs/2309.15570