Coarse selectors of groups

For a group \(G\), \(\mathcal{F}_G\) denotes the set of all non-empty finite subsets of \(G\). We extend the finitary coarse structure of \(G\) from \(G\times G\) to \(\mathcal{F}_G\times \mathcal{F}_G\) and say that a macro-uniform mapping \(f\colon \mathcal{F}_G \to \mathcal{F}_G\) (resp. \(f\colo...

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Date:2023
Main Author: Protasov, I.
Format: Article
Language:English
Published: Lugansk National Taras Shevchenko University 2023
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Online Access:https://admjournal.luguniv.edu.ua/index.php/adm/article/view/2127
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Journal Title:Algebra and Discrete Mathematics

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Algebra and Discrete Mathematics
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author Protasov, I.
author_facet Protasov, I.
author_sort Protasov, I.
baseUrl_str
collection OJS
datestamp_date 2023-10-30T03:22:37Z
description For a group \(G\), \(\mathcal{F}_G\) denotes the set of all non-empty finite subsets of \(G\). We extend the finitary coarse structure of \(G\) from \(G\times G\) to \(\mathcal{F}_G\times \mathcal{F}_G\) and say that a macro-uniform mapping \(f\colon \mathcal{F}_G \to \mathcal{F}_G\) (resp. \(f\colon [G]^2 \to G\)) is a finitary selector (resp. 2-selector) of \(G\) if \(f(A)\in A\) for each \(A\in \mathcal{F}_G\) (resp. \( A \in [G]^2 \)). We prove that a group \(G\) admits a finitary selector if and only if \(G\) admits a 2-selector and if and only if \(G\) is a finite extension of an infinite cyclic subgroup or \(G\) is countable and locally finite. We use this result to characterize groups admitting linear orders compatible with finitary coarse structures.
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spelling admjournalluguniveduua-article-21272023-10-30T03:22:37Z Coarse selectors of groups Protasov, I. finitary coarse structure, Cayley graph, selector 20F69, 54C65 For a group \(G\), \(\mathcal{F}_G\) denotes the set of all non-empty finite subsets of \(G\). We extend the finitary coarse structure of \(G\) from \(G\times G\) to \(\mathcal{F}_G\times \mathcal{F}_G\) and say that a macro-uniform mapping \(f\colon \mathcal{F}_G \to \mathcal{F}_G\) (resp. \(f\colon [G]^2 \to G\)) is a finitary selector (resp. 2-selector) of \(G\) if \(f(A)\in A\) for each \(A\in \mathcal{F}_G\) (resp. \( A \in [G]^2 \)). We prove that a group \(G\) admits a finitary selector if and only if \(G\) admits a 2-selector and if and only if \(G\) is a finite extension of an infinite cyclic subgroup or \(G\) is countable and locally finite. We use this result to characterize groups admitting linear orders compatible with finitary coarse structures. Lugansk National Taras Shevchenko University 2023-10-12 Article Article Peer-reviewed Article application/pdf https://admjournal.luguniv.edu.ua/index.php/adm/article/view/2127 10.12958/adm2127 Algebra and Discrete Mathematics; Vol 35, No 2 (2023) 2415-721X 1726-3255 en https://admjournal.luguniv.edu.ua/index.php/adm/article/view/2127/pdf https://admjournal.luguniv.edu.ua/index.php/adm/article/downloadSuppFile/2127/1093 Copyright (c) 2023 Algebra and Discrete Mathematics
spellingShingle finitary coarse structure
Cayley graph
selector
20F69
54C65
Protasov, I.
Coarse selectors of groups
title Coarse selectors of groups
title_full Coarse selectors of groups
title_fullStr Coarse selectors of groups
title_full_unstemmed Coarse selectors of groups
title_short Coarse selectors of groups
title_sort coarse selectors of groups
topic finitary coarse structure
Cayley graph
selector
20F69
54C65
topic_facet finitary coarse structure
Cayley graph
selector
20F69
54C65
url https://admjournal.luguniv.edu.ua/index.php/adm/article/view/2127
work_keys_str_mv AT protasovi coarseselectorsofgroups