Algebra in superextensions of groups, II: cancelativity and centers

Given a countable group \(X\) we study the algebraic structure of itssuperextension   \(\lambda(X)\). This is a right-topological semigroup consisting of all  maximal linked systems  on \(X\) endowed with the operation   \(\mathcal A\circ\mathcal B=\{C\subset  X:\{x\in X:x^{-1}C\in\mathcal B\}\in\ma...

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Дата:2018
Автори: Banakh, Taras, Gavrylkiv, Volodymyr
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/823
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Назва журналу:Algebra and Discrete Mathematics

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Algebra and Discrete Mathematics
id oai:ojs.admjournal.luguniv.edu.ua:article-823
record_format ojs
spelling oai:ojs.admjournal.luguniv.edu.ua:article-8232018-03-22T09:57:42Z Algebra in superextensions of groups, II: cancelativity and centers Banakh, Taras Gavrylkiv, Volodymyr Superextension, right-topological semigroup, cancelable element, topological center, algebraic center 20M99, 54B20 Given a countable group \(X\) we study the algebraic structure of itssuperextension   \(\lambda(X)\). This is a right-topological semigroup consisting of all  maximal linked systems  on \(X\) endowed with the operation   \(\mathcal A\circ\mathcal B=\{C\subset  X:\{x\in X:x^{-1}C\in\mathcal B\}\in\mathcal A\}\)  that extends the group operation of \(X\). We show that the subsemigroup \(\lambda^\circ(X)\) of free maximal linked systems contains an open dense subset of right cancelable elements. Also we prove that the topological center of \(\lambda(X)\) coincides with the subsemigroup \(\lambda^\bullet(X)\) of all maximal linked systems with finite support. This result is applied to show that the algebraic center of \(\lambda(X)\) coincides with the algebraic center of \(X\) provided \(X\) is countably infinite. On the other hand, for finite groups \(X\) of order \(3\le|X|\le5\) the algebraic center of \(\lambda(X)\) is strictly larger than the algebraic center of \(X\). Lugansk National Taras Shevchenko University 2018-03-22 Article Article Peer-reviewed Article application/pdf https://admjournal.luguniv.edu.ua/index.php/adm/article/view/823 Algebra and Discrete Mathematics; Vol 7, No 4 (2008) 2415-721X 1726-3255 en https://admjournal.luguniv.edu.ua/index.php/adm/article/view/823/353 Copyright (c) 2018 Algebra and Discrete Mathematics
institution Algebra and Discrete Mathematics
collection OJS
language English
topic Superextension
right-topological semigroup
cancelable element
topological center
algebraic center
20M99
54B20
spellingShingle Superextension
right-topological semigroup
cancelable element
topological center
algebraic center
20M99
54B20
Banakh, Taras
Gavrylkiv, Volodymyr
Algebra in superextensions of groups, II: cancelativity and centers
topic_facet Superextension
right-topological semigroup
cancelable element
topological center
algebraic center
20M99
54B20
format Article
author Banakh, Taras
Gavrylkiv, Volodymyr
author_facet Banakh, Taras
Gavrylkiv, Volodymyr
author_sort Banakh, Taras
title Algebra in superextensions of groups, II: cancelativity and centers
title_short Algebra in superextensions of groups, II: cancelativity and centers
title_full Algebra in superextensions of groups, II: cancelativity and centers
title_fullStr Algebra in superextensions of groups, II: cancelativity and centers
title_full_unstemmed Algebra in superextensions of groups, II: cancelativity and centers
title_sort algebra in superextensions of groups, ii: cancelativity and centers
description Given a countable group \(X\) we study the algebraic structure of itssuperextension   \(\lambda(X)\). This is a right-topological semigroup consisting of all  maximal linked systems  on \(X\) endowed with the operation   \(\mathcal A\circ\mathcal B=\{C\subset  X:\{x\in X:x^{-1}C\in\mathcal B\}\in\mathcal A\}\)  that extends the group operation of \(X\). We show that the subsemigroup \(\lambda^\circ(X)\) of free maximal linked systems contains an open dense subset of right cancelable elements. Also we prove that the topological center of \(\lambda(X)\) coincides with the subsemigroup \(\lambda^\bullet(X)\) of all maximal linked systems with finite support. This result is applied to show that the algebraic center of \(\lambda(X)\) coincides with the algebraic center of \(X\) provided \(X\) is countably infinite. On the other hand, for finite groups \(X\) of order \(3\le|X|\le5\) the algebraic center of \(\lambda(X)\) is strictly larger than the algebraic center of \(X\).
publisher Lugansk National Taras Shevchenko University
publishDate 2018
url https://admjournal.luguniv.edu.ua/index.php/adm/article/view/823
work_keys_str_mv AT banakhtaras algebrainsuperextensionsofgroupsiicancelativityandcenters
AT gavrylkivvolodymyr algebrainsuperextensionsofgroupsiicancelativityandcenters
first_indexed 2024-04-12T06:25:51Z
last_indexed 2024-04-12T06:25:51Z
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