On certain semigroups of contraction mappings of a finite chain

Let [n] = {1, 2, . . . , n} be a finite chain and let Pn (resp. , Tn) be the semigroup of partial transformations on [n] (resp. , full transformations on [n]). Let CPn = {α ∈ Pn : (for all x, y ∈ Dom α) |xα−yα| ≤ |x−y|} (resp. , CT n = {α ∈ Tn : (for all x, y ∈ [n]) |xα−yα| ≤ |x−y|} ) be the subsemi...

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Опубліковано в: :Algebra and Discrete Mathematics
Дата:2021
Автори: Umar, A., Zubairu, M.M.
Формат: Стаття
Мова:English
Опубліковано: Інститут прикладної математики і механіки НАН України 2021
Онлайн доступ:https://nasplib.isofts.kiev.ua/handle/123456789/188755
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Назва журналу:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Цитувати:On certain semigroups of contraction mappings of a finite chain / A. Umar, M.M. Zubairu // Algebra and Discrete Mathematics. — 2021. — Vol. 32, № 2. — С. 299-320. — Бібліогр.: 37 назв. — англ.

Репозитарії

Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-188755
record_format dspace
spelling Umar, A.
Zubairu, M.M.
2023-03-14T17:16:37Z
2023-03-14T17:16:37Z
2021
On certain semigroups of contraction mappings of a finite chain / A. Umar, M.M. Zubairu // Algebra and Discrete Mathematics. — 2021. — Vol. 32, № 2. — С. 299-320. — Бібліогр.: 37 назв. — англ.
1726-3255
DOI:10.12958/adm1816
2020 MSC: 20M20.
https://nasplib.isofts.kiev.ua/handle/123456789/188755
Let [n] = {1, 2, . . . , n} be a finite chain and let Pn (resp. , Tn) be the semigroup of partial transformations on [n] (resp. , full transformations on [n]). Let CPn = {α ∈ Pn : (for all x, y ∈ Dom α) |xα−yα| ≤ |x−y|} (resp. , CT n = {α ∈ Tn : (for all x, y ∈ [n]) |xα−yα| ≤ |x−y|} ) be the subsemigroup of partial contraction mappings on [n] (resp. , subsemigroup of full contraction mappings on [n]). We characterize all the starred Green’s relations on CPn and it subsemigroup of order preserving and/or order reversing and subsemigroup of order preserving partial contractions on [n], respectively. We show that the semigroups CPn and CT n, and some of their subsemigroups are left abundant semigroups for all n but not right abundant for n ≥ 4. We further show that the set of regular elements of the semigroup CT n and its subsemigroup of order preserving or order reversing full contractions on [n], each forms a regular subsemigroup and an orthodox semigroup, respectively.
The second author would like to thank Bayero University and TET Fund for financial support. He would also like to thank The Petroleum Institute, Khalifa University of Science and Technology for hospitality during his 3-months research visit (November 2017 to February 2018) to the institution. The authors thank the referee for providing useful suggestions.
en
Інститут прикладної математики і механіки НАН України
Algebra and Discrete Mathematics
On certain semigroups of contraction mappings of a finite chain
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title On certain semigroups of contraction mappings of a finite chain
spellingShingle On certain semigroups of contraction mappings of a finite chain
Umar, A.
Zubairu, M.M.
title_short On certain semigroups of contraction mappings of a finite chain
title_full On certain semigroups of contraction mappings of a finite chain
title_fullStr On certain semigroups of contraction mappings of a finite chain
title_full_unstemmed On certain semigroups of contraction mappings of a finite chain
title_sort on certain semigroups of contraction mappings of a finite chain
author Umar, A.
Zubairu, M.M.
author_facet Umar, A.
Zubairu, M.M.
publishDate 2021
language English
container_title Algebra and Discrete Mathematics
publisher Інститут прикладної математики і механіки НАН України
format Article
description Let [n] = {1, 2, . . . , n} be a finite chain and let Pn (resp. , Tn) be the semigroup of partial transformations on [n] (resp. , full transformations on [n]). Let CPn = {α ∈ Pn : (for all x, y ∈ Dom α) |xα−yα| ≤ |x−y|} (resp. , CT n = {α ∈ Tn : (for all x, y ∈ [n]) |xα−yα| ≤ |x−y|} ) be the subsemigroup of partial contraction mappings on [n] (resp. , subsemigroup of full contraction mappings on [n]). We characterize all the starred Green’s relations on CPn and it subsemigroup of order preserving and/or order reversing and subsemigroup of order preserving partial contractions on [n], respectively. We show that the semigroups CPn and CT n, and some of their subsemigroups are left abundant semigroups for all n but not right abundant for n ≥ 4. We further show that the set of regular elements of the semigroup CT n and its subsemigroup of order preserving or order reversing full contractions on [n], each forms a regular subsemigroup and an orthodox semigroup, respectively.
issn 1726-3255
url https://nasplib.isofts.kiev.ua/handle/123456789/188755
citation_txt On certain semigroups of contraction mappings of a finite chain / A. Umar, M.M. Zubairu // Algebra and Discrete Mathematics. — 2021. — Vol. 32, № 2. — С. 299-320. — Бібліогр.: 37 назв. — англ.
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