Results 191 to 200 of about 1,661 (220)

On left regular and intra-regular ordered semigroups

open access: yesMathematica Slovaca, 2014
We study the decomposition of left regular ordered semigroups into left regular components and the decomposition of intra-regular ordered semigroups into simple or intra-regular components, adding some additional information to the results considered in [
Niovi Kehayopulu, Michael Tsingelis
exaly   +1 more source

Regular Orthocryptou Semigroups

Semigroup Forum, 2004
The semigroups in this paper are defined using two kinds of generalized Green's relations defined elsewhere. A semigroup \(S\) is superabundant if each \(H^*\)-class contains an idempotent and \(S\) is semisuperabundant if both each \(\widetilde L\)- and \(\widetilde R\)-class contains at least one idempotent. A semigroup is a \(u\)-semigroup if it has
Wang, Zhengpan, Zhang, Ronghua, Xie, Mu
openaire   +2 more sources

On Weak Regular *-semigroups

Acta Mathematica Sinica, English Series, 2004
A semigroup \(S\) is called a weak regular *-semigroup if it has a unary operation * satisfying \[ xx^*x=x,\;(x^*)^*=x,\text{ and }(xx^*yy^*)^*=yy^*xx^*\text{ for all }x,y\text{ in }S. \] In this paper a type of partial algebra called a projective partial groupoid is defined.
Li, Yonghua, Kan, Haibin, Yu, Bingjun
openaire   +2 more sources

Flows on Regular Semigroups

Applied Categorical Structures, 2003
Let \(\mathbf C\) be a category with vertex set \(V\) and arrow set \(A\). For \(a\in A\), \(a\sigma\in V\) is the source of \(a\) and \(a\tau\in V\) is the target of \(a\). A flow of \(\mathbf C\) is a mapping \(\varphi\colon V\to A\) such that \((x\varphi)\sigma=x\) for all \(x\in V\).
openaire   +1 more source

Variants of Regular Semigroups

Semigroup Forum, 2001
Let \(S\) be a semigroup and \(a\in S\); the semigroup with underlying set \(S\) and multiplication \(\circ\) defined by \(x\circ y=xay\) is a variant of \(S\), denoted \((S,a)\). An element of a regular semigroup is regularity preserving if \((S,a)\) is regular.
Khan, T. A., Lawson, M. V.
openaire   +2 more sources

Weakly regular *-semigroups

Semigroup Forum, 1999
A regular \(*\)-semigroup is a semigroup \(S\) endowed with a supplementary operation \(*\) satisfying: (1) \(xx^*=x\), for every \(x\in S\); (2) \((x^*)^*=x\), for every \(x\in S\); (3) \((xy)^*=y^*x^*\), for every \(x,y\) in \(S\). It has been proved by \textit{M.
openaire   +2 more sources

On Ordered Semigroups Which are Semilattices of Simple and Regular Semigroups

open access: yesCommunications in Algebra, 2013
We characterize the ordered semigroups which are decomposable into simple and regular components. We prove that each ordered semigroup which is both regular and intra-regular is decomposable into simple and regular semigroups, and the converse statement ...
Niovi Kehayopulu, Michael Tsingelis
exaly   +1 more source

Left (Right) Regular Elements of Some Transformation Semigroups

Mathematics, 2023
Ekkachai Laysirikul   +1 more
exaly  

℘-Regular semigroups

Semigroup Forum, 1989
M. Yamada, M. K. Sen
openaire   +1 more source

On Left Regular Ordered Semigroups

Southeast Asian Bulletin of Mathematics, 2002
Niovi Kehayopulu   +2 more
exaly  

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