Extending and improving conical bicombings

Fuente: arXiv
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Main Author: Basso, Giuliano
Format: Preprint
Published: 2020
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author Basso, Giuliano
author_facet Basso, Giuliano
contents We study metric spaces that admit a conical bicombing and thus obey a weak form of non-positive curvature. Prime examples of such spaces are injective metric spaces. In this article we give a complete characterization of complete metric spaces admitting a conical bicombing by showing that every such space is isometric to a closed $σ$-convex subset of some injective metric space. In addition, we show that every proper metric space that admits a conical bicombing also admits a consistent bicombing that satisfies certain convexity conditions. This can be seen as a strong indication that a question from Descombes and Lang about improving conical bicombings might have a positive answer. As an application, we prove that any group acting geometrically on a proper metric space with a conical bicombing admits a $\mathcal{Z}$-structure.
format Preprint
id arxiv_https___arxiv_org_abs_2005_13941
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Extending and improving conical bicombings
Basso, Giuliano
Metric Geometry
53C23 (Primary) 20F65, 51F99 (Secondary)
We study metric spaces that admit a conical bicombing and thus obey a weak form of non-positive curvature. Prime examples of such spaces are injective metric spaces. In this article we give a complete characterization of complete metric spaces admitting a conical bicombing by showing that every such space is isometric to a closed $σ$-convex subset of some injective metric space. In addition, we show that every proper metric space that admits a conical bicombing also admits a consistent bicombing that satisfies certain convexity conditions. This can be seen as a strong indication that a question from Descombes and Lang about improving conical bicombings might have a positive answer. As an application, we prove that any group acting geometrically on a proper metric space with a conical bicombing admits a $\mathcal{Z}$-structure.
title Extending and improving conical bicombings
topic Metric Geometry
53C23 (Primary) 20F65, 51F99 (Secondary)
url https://arxiv.org/abs/2005.13941