Back-and-forth equivalent group von Neumann algebras

Fuente: arXiv
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Main Authors: Goldbring, Isaac, Harrison-Trainor, Matthew
Format: Preprint
Published: 2024
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author Goldbring, Isaac
Harrison-Trainor, Matthew
author_facet Goldbring, Isaac
Harrison-Trainor, Matthew
contents We prove that if $G$ and $H$ are $α$-back-and-forth equivalent groups (in the sense of computable structure theory) for some ordinal $α\geq ω$, then their group von Neumann algebras $L(G)$ and $L(H)$ are also $α$-back-and-forth equivalent. In particular, if $G$ and $H$ are $ω$-back-and-forth-equivalent groups, then $L(G)$ and $L(H)$ are elementarily equivalent; this is known to fail under the weaker hypothesis that $G$ and $H$ are merely elementarily equivalent. We extend this result to crossed product von Neumann algebras associated to Bernoulli actions of back-and-forth equivalent groups.
format Preprint
id arxiv_https___arxiv_org_abs_2403_16181
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Back-and-forth equivalent group von Neumann algebras
Goldbring, Isaac
Harrison-Trainor, Matthew
Logic
Operator Algebras
We prove that if $G$ and $H$ are $α$-back-and-forth equivalent groups (in the sense of computable structure theory) for some ordinal $α\geq ω$, then their group von Neumann algebras $L(G)$ and $L(H)$ are also $α$-back-and-forth equivalent. In particular, if $G$ and $H$ are $ω$-back-and-forth-equivalent groups, then $L(G)$ and $L(H)$ are elementarily equivalent; this is known to fail under the weaker hypothesis that $G$ and $H$ are merely elementarily equivalent. We extend this result to crossed product von Neumann algebras associated to Bernoulli actions of back-and-forth equivalent groups.
title Back-and-forth equivalent group von Neumann algebras
topic Logic
Operator Algebras
url https://arxiv.org/abs/2403.16181