Structural properties of extremal asymmetric colorings

Let \(\Omega\) be a space with probability measure \(\mu\) for which the notion of symmetry is defined. Given \(A\subseteq\Omega\), let \( ms(A)\) denote the supremum of \(\mu(B)\) over symmetric \(B\subseteq A\). An \(r\)-coloring of \(\Omega\) is a measurable map \(\chi\ : \Omega \rightarrow \{1,\...

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Бібліографічні деталі
Дата:2018
Автор: Verbitsky, Oleg
Формат: Стаття
Мова:English
Опубліковано: Lugansk National Taras Shevchenko University 2018
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Онлайн доступ:https://admjournal.luguniv.edu.ua/index.php/adm/article/view/975
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Назва журналу:Algebra and Discrete Mathematics

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Algebra and Discrete Mathematics
id admjournalluguniveduua-article-975
record_format ojs
spelling admjournalluguniveduua-article-9752018-05-14T07:18:11Z Structural properties of extremal asymmetric colorings Verbitsky, Oleg continuous Ramsey theory, asymmetric colorings, symmetry of a Euclidean space, polyominoes 05D10 Let \(\Omega\) be a space with probability measure \(\mu\) for which the notion of symmetry is defined. Given \(A\subseteq\Omega\), let \( ms(A)\) denote the supremum of \(\mu(B)\) over symmetric \(B\subseteq A\). An \(r\)-coloring of \(\Omega\) is a measurable map \(\chi\ : \Omega \rightarrow \{1,\ldots,r\}\) possibly undefined on a set of measure 0. Given an \(r\)-coloring \(\chi\), let \(ms(\Omega;\chi)=\max_{1\le i\le  r} ms(\chi^{-1}(i))\). With each space \(\Omega\) we associate a Ramsey type number \(ms(\Omega,r)=\inf_\chi ms(\Omega;\chi)\). We call a coloring \(\chi\) congruent if the monochromatic classes \(\chi^{-1}(1),\ldots,\chi^{-1}(r)\) are pairwise congruent, i.e., can be mapped onto each other by a symmetry of \(\Omega\). We define \( ms^\star(\Omega,r)\) to be the infimum of \(ms(\Omega;\chi)\) over congruent \(\chi\).We prove that \( ms(S^1,r)=ms^\star(S^1,r)\) for the unitary circle \(S^1\) endowed with standard symmetries of a plane, estimate \(ms^\star([0,1),r)\) for the unitary interval of reals considered with central symmetry, and explore some other regularity properties of extremal colorings for various spaces. Lugansk National Taras Shevchenko University 2018-05-14 Article Article Peer-reviewed Article application/pdf https://admjournal.luguniv.edu.ua/index.php/adm/article/view/975 Algebra and Discrete Mathematics; Vol 2, No 4 (2003) 2415-721X 1726-3255 en https://admjournal.luguniv.edu.ua/index.php/adm/article/view/975/504 Copyright (c) 2018 Algebra and Discrete Mathematics
institution Algebra and Discrete Mathematics
baseUrl_str
datestamp_date 2018-05-14T07:18:11Z
collection OJS
language English
topic continuous Ramsey theory
asymmetric colorings
symmetry of a Euclidean space
polyominoes
05D10
spellingShingle continuous Ramsey theory
asymmetric colorings
symmetry of a Euclidean space
polyominoes
05D10
Verbitsky, Oleg
Structural properties of extremal asymmetric colorings
topic_facet continuous Ramsey theory
asymmetric colorings
symmetry of a Euclidean space
polyominoes
05D10
format Article
author Verbitsky, Oleg
author_facet Verbitsky, Oleg
author_sort Verbitsky, Oleg
title Structural properties of extremal asymmetric colorings
title_short Structural properties of extremal asymmetric colorings
title_full Structural properties of extremal asymmetric colorings
title_fullStr Structural properties of extremal asymmetric colorings
title_full_unstemmed Structural properties of extremal asymmetric colorings
title_sort structural properties of extremal asymmetric colorings
description Let \(\Omega\) be a space with probability measure \(\mu\) for which the notion of symmetry is defined. Given \(A\subseteq\Omega\), let \( ms(A)\) denote the supremum of \(\mu(B)\) over symmetric \(B\subseteq A\). An \(r\)-coloring of \(\Omega\) is a measurable map \(\chi\ : \Omega \rightarrow \{1,\ldots,r\}\) possibly undefined on a set of measure 0. Given an \(r\)-coloring \(\chi\), let \(ms(\Omega;\chi)=\max_{1\le i\le  r} ms(\chi^{-1}(i))\). With each space \(\Omega\) we associate a Ramsey type number \(ms(\Omega,r)=\inf_\chi ms(\Omega;\chi)\). We call a coloring \(\chi\) congruent if the monochromatic classes \(\chi^{-1}(1),\ldots,\chi^{-1}(r)\) are pairwise congruent, i.e., can be mapped onto each other by a symmetry of \(\Omega\). We define \( ms^\star(\Omega,r)\) to be the infimum of \(ms(\Omega;\chi)\) over congruent \(\chi\).We prove that \( ms(S^1,r)=ms^\star(S^1,r)\) for the unitary circle \(S^1\) endowed with standard symmetries of a plane, estimate \(ms^\star([0,1),r)\) for the unitary interval of reals considered with central symmetry, and explore some other regularity properties of extremal colorings for various spaces.
publisher Lugansk National Taras Shevchenko University
publishDate 2018
url https://admjournal.luguniv.edu.ua/index.php/adm/article/view/975
work_keys_str_mv AT verbitskyoleg structuralpropertiesofextremalasymmetriccolorings
first_indexed 2025-12-02T15:43:46Z
last_indexed 2025-12-02T15:43:46Z
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