Edge subdivisions and the $L^2$-homology of right-angled Coxeter groups

Fuente: arXiv
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Auteurs principaux: Avramidi, Grigori, Okun, Boris, Schreve, Kevin
Format: Preprint
Publié: 2024
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author Avramidi, Grigori
Okun, Boris
Schreve, Kevin
author_facet Avramidi, Grigori
Okun, Boris
Schreve, Kevin
contents If $L$ is a flag triangulation of $S^{n-1}$, then the Davis complex $Σ_L$ for the associated right-angled Coxeter group $W_L$ is a contractible $n$-manifold. A special case of a conjecture of Singer predicts that the $L^2$-homology of such $Σ_L$ vanishes outside the middle dimension. We give conditions which guarantee this vanishing is preserved under edge subdivision of $L$. In particular, we verify Singer's conjecture when $L$ is the barycentric subdivision of the boundary of an $n$-simplex, and for general barycentric subdivisions of triangulations of $S^{2n-1}$. Using this, we construct explicit counterexamples to a torsion growth analogue of Singer's conjecture.
format Preprint
id arxiv_https___arxiv_org_abs_2411_08009
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Edge subdivisions and the $L^2$-homology of right-angled Coxeter groups
Avramidi, Grigori
Okun, Boris
Schreve, Kevin
Geometric Topology
Group Theory
If $L$ is a flag triangulation of $S^{n-1}$, then the Davis complex $Σ_L$ for the associated right-angled Coxeter group $W_L$ is a contractible $n$-manifold. A special case of a conjecture of Singer predicts that the $L^2$-homology of such $Σ_L$ vanishes outside the middle dimension. We give conditions which guarantee this vanishing is preserved under edge subdivision of $L$. In particular, we verify Singer's conjecture when $L$ is the barycentric subdivision of the boundary of an $n$-simplex, and for general barycentric subdivisions of triangulations of $S^{2n-1}$. Using this, we construct explicit counterexamples to a torsion growth analogue of Singer's conjecture.
title Edge subdivisions and the $L^2$-homology of right-angled Coxeter groups
topic Geometric Topology
Group Theory
url https://arxiv.org/abs/2411.08009