Some combinatorial problems in the theory of partial transformation semigroups

Let \(X_n = \{1, 2, \ldots , n\}\). On a partial transformation \(\alpha : \mathop{\rm Dom}\nolimits \alpha \subseteq  X_n \rightarrow \mbox{Im}\,\alpha \subseteq X_n\) of \(X_n\) the following parameters are defined: the  breadth  or  width of \(\alpha\) is \(\mid{\mathop{\rm Dom}\nolimits}\  \alph...

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Date:2018
Main Author: Umar, A.
Format: Article
Language:English
Published: Lugansk National Taras Shevchenko University 2018
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Online Access:https://admjournal.luguniv.edu.ua/index.php/adm/article/view/1027
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Journal Title:Algebra and Discrete Mathematics

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Algebra and Discrete Mathematics
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spelling admjournalluguniveduua-article-10272018-04-26T01:41:11Z Some combinatorial problems in the theory of partial transformation semigroups Umar, A. full transformation, partial transformation, breadth, collapse, fix, height and right (left) waist of a transformation. Idempotents and nilpotents 20M17, 20M20, 05A10, 05A15 Let \(X_n = \{1, 2, \ldots , n\}\). On a partial transformation \(\alpha : \mathop{\rm Dom}\nolimits \alpha \subseteq  X_n \rightarrow \mbox{Im}\,\alpha \subseteq X_n\) of \(X_n\) the following parameters are defined: the  breadth  or  width of \(\alpha\) is \(\mid{\mathop{\rm Dom}\nolimits}\  \alpha\mid\), the collapse of \(\alpha\) is \(c(\alpha)=\mid\cup_{t \in \mbox{Im} \alpha}\{t \alpha^{-1}: \mid t\alpha^{-1}\mid \geq 2\}\mid\), fix of \(\alpha\) is \(f(\alpha) = \mid\{x \in X_n: x\alpha = x\}\mid\), the  height of \(\alpha\) is \(\mid\mbox{Im}\,\alpha\mid\), and the right [left] waist of \(\alpha\) is \(\max(\mbox{Im}\,\alpha)\, [\min(\mbox{Im}\,\alpha)]\). The cardinalities of some equivalences defined by equalities of these parameters on \({\cal T}_n\), the semigroup of full transformations of \(X_n\), and \({\cal P}_n\) the semigroup of partial transformations of \(X_n\) and some of their notable subsemigroups that have been computed are gathered together and the open problems highlighted. Lugansk National Taras Shevchenko University 2018-04-26 Article Article Peer-reviewed Article application/pdf https://admjournal.luguniv.edu.ua/index.php/adm/article/view/1027 Algebra and Discrete Mathematics; Vol 17, No 1 (2014) 2415-721X 1726-3255 en https://admjournal.luguniv.edu.ua/index.php/adm/article/view/1027/551 Copyright (c) 2018 Algebra and Discrete Mathematics
institution Algebra and Discrete Mathematics
baseUrl_str
datestamp_date 2018-04-26T01:41:11Z
collection OJS
language English
topic full transformation
partial transformation
breadth
collapse
fix
height and right (left) waist of a transformation. Idempotents and nilpotents
20M17
20M20
05A10
05A15
spellingShingle full transformation
partial transformation
breadth
collapse
fix
height and right (left) waist of a transformation. Idempotents and nilpotents
20M17
20M20
05A10
05A15
Umar, A.
Some combinatorial problems in the theory of partial transformation semigroups
topic_facet full transformation
partial transformation
breadth
collapse
fix
height and right (left) waist of a transformation. Idempotents and nilpotents
20M17
20M20
05A10
05A15
format Article
author Umar, A.
author_facet Umar, A.
author_sort Umar, A.
title Some combinatorial problems in the theory of partial transformation semigroups
title_short Some combinatorial problems in the theory of partial transformation semigroups
title_full Some combinatorial problems in the theory of partial transformation semigroups
title_fullStr Some combinatorial problems in the theory of partial transformation semigroups
title_full_unstemmed Some combinatorial problems in the theory of partial transformation semigroups
title_sort some combinatorial problems in the theory of partial transformation semigroups
description Let \(X_n = \{1, 2, \ldots , n\}\). On a partial transformation \(\alpha : \mathop{\rm Dom}\nolimits \alpha \subseteq  X_n \rightarrow \mbox{Im}\,\alpha \subseteq X_n\) of \(X_n\) the following parameters are defined: the  breadth  or  width of \(\alpha\) is \(\mid{\mathop{\rm Dom}\nolimits}\  \alpha\mid\), the collapse of \(\alpha\) is \(c(\alpha)=\mid\cup_{t \in \mbox{Im} \alpha}\{t \alpha^{-1}: \mid t\alpha^{-1}\mid \geq 2\}\mid\), fix of \(\alpha\) is \(f(\alpha) = \mid\{x \in X_n: x\alpha = x\}\mid\), the  height of \(\alpha\) is \(\mid\mbox{Im}\,\alpha\mid\), and the right [left] waist of \(\alpha\) is \(\max(\mbox{Im}\,\alpha)\, [\min(\mbox{Im}\,\alpha)]\). The cardinalities of some equivalences defined by equalities of these parameters on \({\cal T}_n\), the semigroup of full transformations of \(X_n\), and \({\cal P}_n\) the semigroup of partial transformations of \(X_n\) and some of their notable subsemigroups that have been computed are gathered together and the open problems highlighted.
publisher Lugansk National Taras Shevchenko University
publishDate 2018
url https://admjournal.luguniv.edu.ua/index.php/adm/article/view/1027
work_keys_str_mv AT umara somecombinatorialproblemsinthetheoryofpartialtransformationsemigroups
first_indexed 2025-12-02T15:38:09Z
last_indexed 2025-12-02T15:38:09Z
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