Asymptotically CAT(0) metrics, Z-structures, and the Farrell-Jones Conjecture

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Autores principales: Durham, Matthew Gentry, Minsky, Yair, Sisto, Alessandro
Formato: Preprint
Publicado: 2025
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author Durham, Matthew Gentry
Minsky, Yair
Sisto, Alessandro
author_facet Durham, Matthew Gentry
Minsky, Yair
Sisto, Alessandro
contents We show that colorable hierarchically hyperbolic groups (HHGs) admit asymptotically CAT(0) metrics, that is, roughly, metrics where the CAT(0) inequality holds up to sublinear error in the size of the triangle. We use the asymptotically CAT(0) metrics to construct contractible simplicial complexes and compactifications that provide $\mathcal{Z}$-structures in the sense of Bestvina and Dranishnikov. It was previously unknown that mapping class groups are asymptotically CAT(0) and admit $\mathcal{Z}$-structures. As an application, we prove that many HHGs satisfy the Farrell--Jones Conjecture, including extra large-type Artin groups. To construct asymptotically CAT(0) metrics, we show that hulls of finitely many points in a colorable HHGs can be approximated by CAT(0) cube complexes in a way that adding a point to the finite set corresponds, up to finitely many hyperplanes deletions, to a convex embedding.
format Preprint
id arxiv_https___arxiv_org_abs_2504_17048
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Asymptotically CAT(0) metrics, Z-structures, and the Farrell-Jones Conjecture
Durham, Matthew Gentry
Minsky, Yair
Sisto, Alessandro
Geometric Topology
Group Theory
Metric Geometry
20F67, 20F65, 20F69, 57K20
We show that colorable hierarchically hyperbolic groups (HHGs) admit asymptotically CAT(0) metrics, that is, roughly, metrics where the CAT(0) inequality holds up to sublinear error in the size of the triangle. We use the asymptotically CAT(0) metrics to construct contractible simplicial complexes and compactifications that provide $\mathcal{Z}$-structures in the sense of Bestvina and Dranishnikov. It was previously unknown that mapping class groups are asymptotically CAT(0) and admit $\mathcal{Z}$-structures. As an application, we prove that many HHGs satisfy the Farrell--Jones Conjecture, including extra large-type Artin groups. To construct asymptotically CAT(0) metrics, we show that hulls of finitely many points in a colorable HHGs can be approximated by CAT(0) cube complexes in a way that adding a point to the finite set corresponds, up to finitely many hyperplanes deletions, to a convex embedding.
title Asymptotically CAT(0) metrics, Z-structures, and the Farrell-Jones Conjecture
topic Geometric Topology
Group Theory
Metric Geometry
20F67, 20F65, 20F69, 57K20
url https://arxiv.org/abs/2504.17048