The semigroup of nonempty finite subsets of integers

Let Z be the additive group of integers and g the semigroup consisting of all nonempty finite subsets of Z with respect to the operation defined byA+B={a+b:a∈A,   b∈B},   A,B∈g.For X∈g, define AX to be the basis of 〈X−min(X)〉 and BX the basis of 〈max(X)−X〉. In the greatest semilattice decomposition...

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Main Author: Reuben Spake
Format: Article
Language:English
Published: Wiley 1986-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Subjects:
Online Access:http://dx.doi.org/10.1155/S0161171286000765
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author Reuben Spake
author_facet Reuben Spake
author_sort Reuben Spake
collection DOAJ
description Let Z be the additive group of integers and g the semigroup consisting of all nonempty finite subsets of Z with respect to the operation defined byA+B={a+b:a∈A,   b∈B},   A,B∈g.For X∈g, define AX to be the basis of 〈X−min(X)〉 and BX the basis of 〈max(X)−X〉. In the greatest semilattice decomposition of g, let α(X) denote the archimedean component containing X and define α0(X)={Y∈α(X):min(Y)=0}. In this paper we examine the structure of g and determine its greatest semilattice decomposition. In particular, we show that for X,Y∈g, α(X)=α(Y) if and only if AX=AY and BX=BY. Furthermore, if X∈g is a non-singleton, then the idempotent-free α(X) is isomorphic to the direct product of the (idempotent-free) power joined subsemigroup α0(X) and the group Z.
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spelling doaj-art-8fd38e09915a43a69e7b842956c8e5912025-02-03T01:30:41ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04251986-01-019360561610.1155/S0161171286000765The semigroup of nonempty finite subsets of integersReuben Spake0Department of Mathematics, University of California, Davis 95616, California, USALet Z be the additive group of integers and g the semigroup consisting of all nonempty finite subsets of Z with respect to the operation defined byA+B={a+b:a∈A,   b∈B},   A,B∈g.For X∈g, define AX to be the basis of 〈X−min(X)〉 and BX the basis of 〈max(X)−X〉. In the greatest semilattice decomposition of g, let α(X) denote the archimedean component containing X and define α0(X)={Y∈α(X):min(Y)=0}. In this paper we examine the structure of g and determine its greatest semilattice decomposition. In particular, we show that for X,Y∈g, α(X)=α(Y) if and only if AX=AY and BX=BY. Furthermore, if X∈g is a non-singleton, then the idempotent-free α(X) is isomorphic to the direct product of the (idempotent-free) power joined subsemigroup α0(X) and the group Z.http://dx.doi.org/10.1155/S0161171286000765greatest semilattice decompositionarchimedean component.
spellingShingle Reuben Spake
The semigroup of nonempty finite subsets of integers
International Journal of Mathematics and Mathematical Sciences
greatest semilattice decomposition
archimedean component.
title The semigroup of nonempty finite subsets of integers
title_full The semigroup of nonempty finite subsets of integers
title_fullStr The semigroup of nonempty finite subsets of integers
title_full_unstemmed The semigroup of nonempty finite subsets of integers
title_short The semigroup of nonempty finite subsets of integers
title_sort semigroup of nonempty finite subsets of integers
topic greatest semilattice decomposition
archimedean component.
url http://dx.doi.org/10.1155/S0161171286000765
work_keys_str_mv AT reubenspake thesemigroupofnonemptyfinitesubsetsofintegers
AT reubenspake semigroupofnonemptyfinitesubsetsofintegers