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Bibliographic Details
Main Author: Gorelov, Alexey
Format: Preprint
Published: 2021
Subjects:
Online Access:https://arxiv.org/abs/2103.16464
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author Gorelov, Alexey
author_facet Gorelov, Alexey
contents We show that a compact polyhedron $P$ collapses to a subpolyhedron $Q$ if and only if it admits a piecewise-linear free deformation retraction onto $Q$. We also consider further possibilities for invariant characterisations of collapsibility in terms of metrics; in this connection, we provide a partial correction to Isbell's claim that every injective metric space is freely contractible, and present a counterexample to a step in the original argument.
format Preprint
id arxiv_https___arxiv_org_abs_2103_16464
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Geometry of collapsing and free deformation retraction
Gorelov, Alexey
Geometric Topology
57Q05, 57Q25
We show that a compact polyhedron $P$ collapses to a subpolyhedron $Q$ if and only if it admits a piecewise-linear free deformation retraction onto $Q$. We also consider further possibilities for invariant characterisations of collapsibility in terms of metrics; in this connection, we provide a partial correction to Isbell's claim that every injective metric space is freely contractible, and present a counterexample to a step in the original argument.
title Geometry of collapsing and free deformation retraction
topic Geometric Topology
57Q05, 57Q25
url https://arxiv.org/abs/2103.16464