Hyperbolic Metric Spaces and Stochastic Embeddings

Stochastic embeddings of finite metric spaces into graph-theoretic trees have proven to be a vital tool for constructing approximation algorithms in theoretical computer science. In the present work, we build out some of the basic theory of stochastic embeddings in the infinite setting with an aim t...

Full description

Saved in:
Bibliographic Details
Main Author: Chris Gartland
Format: Article
Language:English
Published: Cambridge University Press 2025-01-01
Series:Forum of Mathematics, Sigma
Subjects:
Online Access:https://www.cambridge.org/core/product/identifier/S205050942400118X/type/journal_article
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1825206654450270208
author Chris Gartland
author_facet Chris Gartland
author_sort Chris Gartland
collection DOAJ
description Stochastic embeddings of finite metric spaces into graph-theoretic trees have proven to be a vital tool for constructing approximation algorithms in theoretical computer science. In the present work, we build out some of the basic theory of stochastic embeddings in the infinite setting with an aim toward applications to Lipschitz free space theory. We prove that proper metric spaces stochastically embedding into $\mathbb {R}$ -trees have Lipschitz free spaces isomorphic to $L^1$ -spaces. We then undergo a systematic study of stochastic embeddability of Gromov hyperbolic metric spaces into $\mathbb {R}$ -trees by way of stochastic embeddability of their boundaries into ultrametric spaces. The following are obtained as our main results: (1) every snowflake of a compact, finite Nagata-dimensional metric space stochastically embeds into an ultrametric space and has Lipschitz free space isomorphic to $\ell ^1$ , (2) the Lipschitz free space over hyperbolic n-space is isomorphic to the Lipschitz free space over Euclidean n-space and (3) every infinite, finitely generated hyperbolic group stochastically embeds into an $\mathbb {R}$ -tree, has Lipschitz free space isomorphic to $\ell ^1$ , and admits a proper, uniformly Lipschitz affine action on $\ell ^1$ .
format Article
id doaj-art-f429d96eb78143dd894c97ad6699c8e0
institution Kabale University
issn 2050-5094
language English
publishDate 2025-01-01
publisher Cambridge University Press
record_format Article
series Forum of Mathematics, Sigma
spelling doaj-art-f429d96eb78143dd894c97ad6699c8e02025-02-07T07:50:22ZengCambridge University PressForum of Mathematics, Sigma2050-50942025-01-011310.1017/fms.2024.118Hyperbolic Metric Spaces and Stochastic EmbeddingsChris Gartland0Department of Mathematics, University of California San Diego, 9500 Gilman Dr. La Jolla, CA, 92093, USAStochastic embeddings of finite metric spaces into graph-theoretic trees have proven to be a vital tool for constructing approximation algorithms in theoretical computer science. In the present work, we build out some of the basic theory of stochastic embeddings in the infinite setting with an aim toward applications to Lipschitz free space theory. We prove that proper metric spaces stochastically embedding into $\mathbb {R}$ -trees have Lipschitz free spaces isomorphic to $L^1$ -spaces. We then undergo a systematic study of stochastic embeddability of Gromov hyperbolic metric spaces into $\mathbb {R}$ -trees by way of stochastic embeddability of their boundaries into ultrametric spaces. The following are obtained as our main results: (1) every snowflake of a compact, finite Nagata-dimensional metric space stochastically embeds into an ultrametric space and has Lipschitz free space isomorphic to $\ell ^1$ , (2) the Lipschitz free space over hyperbolic n-space is isomorphic to the Lipschitz free space over Euclidean n-space and (3) every infinite, finitely generated hyperbolic group stochastically embeds into an $\mathbb {R}$ -tree, has Lipschitz free space isomorphic to $\ell ^1$ , and admits a proper, uniformly Lipschitz affine action on $\ell ^1$ .https://www.cambridge.org/core/product/identifier/S205050942400118X/type/journal_article51F3020F6730L0546B0346B20
spellingShingle Chris Gartland
Hyperbolic Metric Spaces and Stochastic Embeddings
Forum of Mathematics, Sigma
51F30
20F67
30L05
46B03
46B20
title Hyperbolic Metric Spaces and Stochastic Embeddings
title_full Hyperbolic Metric Spaces and Stochastic Embeddings
title_fullStr Hyperbolic Metric Spaces and Stochastic Embeddings
title_full_unstemmed Hyperbolic Metric Spaces and Stochastic Embeddings
title_short Hyperbolic Metric Spaces and Stochastic Embeddings
title_sort hyperbolic metric spaces and stochastic embeddings
topic 51F30
20F67
30L05
46B03
46B20
url https://www.cambridge.org/core/product/identifier/S205050942400118X/type/journal_article
work_keys_str_mv AT chrisgartland hyperbolicmetricspacesandstochasticembeddings