Mod $p$ and torsion homology growth in nonpositive curvature

Fuente: arXiv
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Main Authors: Avramidi, Grigori, Okun, Boris, Schreve, Kevin
Format: Preprint
Published: 2020
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author Avramidi, Grigori
Okun, Boris
Schreve, Kevin
author_facet Avramidi, Grigori
Okun, Boris
Schreve, Kevin
contents We compute the mod $p$ homology growth of residual sequences of finite index normal subgroups of right-angled Artin groups. We find examples where this differs from the rational homology growth, which implies the homology of subgroups in the sequence has lots of torsion. More precisely, the homology torsion grows exponentially in the index of the subgroup. For odd primes $p$, we construct closed locally CAT(0) manifolds with nonzero mod $p$ homology growth outside the middle dimension. These examples show that Singer's conjecture on rational homology growth and Lück's conjecture on torsion homology growth are incompatible with each other, so at least one of them must be wrong.
format Preprint
id arxiv_https___arxiv_org_abs_2003_01020
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Mod $p$ and torsion homology growth in nonpositive curvature
Avramidi, Grigori
Okun, Boris
Schreve, Kevin
Group Theory
Geometric Topology
We compute the mod $p$ homology growth of residual sequences of finite index normal subgroups of right-angled Artin groups. We find examples where this differs from the rational homology growth, which implies the homology of subgroups in the sequence has lots of torsion. More precisely, the homology torsion grows exponentially in the index of the subgroup. For odd primes $p$, we construct closed locally CAT(0) manifolds with nonzero mod $p$ homology growth outside the middle dimension. These examples show that Singer's conjecture on rational homology growth and Lück's conjecture on torsion homology growth are incompatible with each other, so at least one of them must be wrong.
title Mod $p$ and torsion homology growth in nonpositive curvature
topic Group Theory
Geometric Topology
url https://arxiv.org/abs/2003.01020