Results 111 to 120 of about 1,620 (232)
On Intra-regular Ordered Semigroups
Semigroup Forum, 1998 An ordered semigroup \(S\) is intra-regular if and only if it is a semilattice of simple semigroups, equivalently, if \(S\) is a union of simple subsemigroups of \(S\) [\textit{N. Kehayopulu}, Semigroup Forum 46, 271-278 (1993; Zbl 0776.06013)]. A \(poe\)-semigroup \(S\) is a semilattice of simple semigroups if and only if it is a semilattice of simple
Kehayopulu, N, Tsingelis, M
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A multiplication of e-varieties of regular $E$-solid semigroups by inverse semigroup varieties [PDF]
, 1997 summary:A multiplication of e-varieties of regular $E$-solid semigroups by inverse semigroup varieties is described both semantically and syntactically.
Kuřil, Martin
core
Decompositions of a Krein space in regular subspaces invariant under a uniformly bounded C0-semigroup of bi-contractions [PDF]
, 2004 We give necessary and sufficient conditions under which a C0-semigroup of bi-contractions on a Krein space is similar to a semigroup of contractions on a Hilbert space.
Barsukov, AI +8 more
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On the subsemigroup generated by ordered idempotents of a regular semigroup
, 2015 An element $e$ of an ordered semigroup S is called an ordered idempotent if e ≤ e². Here we characterize the subsemigroup $$ generated by the set of all ordered idempotents of a regular ordered semigroup S.
Bhuniya, Anjan, Kalyan Hansda, Kalyan
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A Characterization of Left Regularity
Universal Journal of Mathematics and Applications, 2019 We show that a zero-symmetric near-ring $N$ is left regular if and only if $N $ is regular and isomorphic to a subdirect product of integral near-rings, where each component is either an Anshel-Clay near-ring or a trivial integral near-ring. We also show
Peter Fuchs
doaj +1 more source
A common framework for restriction semigroups and regular ∗ -semigroups
Journal of Pure and Applied Algebra, 2012 Let \(S\) be a regular \(*\)-semigroup, that is, a semigroup with involution \(a\mapsto a^{-1}\) for which \(a^{-1}\) is an inverse of \(a\). Let \(E_S\) denote the set of idempotents of \(S\) and \(P_S\) the set of \textit{projections} of \(S\), that is, \(P_S=\{e\in E_S:e=e^{-1}\}\).
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Automatic presentations for semigroups
, 2012 Special Issue: 2nd International Conference on Language and Automata Theory and Applications (LATA 2008)This paper applies the concept of FA-presentable structures to semigroups.
Cain, Alan James +3 more
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Regular congruences on an idempotent-regular-surjective semigroup
, 2013 A semigroup $S$ is called \emph{idempotent-surjective} [\emph{regular-surjective}] if whenever $\rho$ is a congruence on $S$ and $a\rho$ is idempotent [regular] in $S/\rho$, then there is $e\in E_S\cap a\rho$ [$r\in Reg(S)\cap a\rho$], where $E_S$ [$Reg ...
Gigoń, R. S.
core
Semigroups of order-decreasing transformations
, 2012 Let X be a totally ordered set and consider the semigroups of orderdecreasing (increasing) full (partial, partial one-to-one) transformations of X. In this Thesis the study of order-increasing full (partial, partial one-to-one) transformations has been
Umar, Abdullahi
core
Regular matrices in the semigroup of hall matrices
, 1993 We study the regular matrices in the semigroup Hn of Hall matrices (Boolean matrices with positive permanent). We study some necessary and sufficient conditions for a Hall matrix to be regular in Hn in terms of idempotent matrices, adjoint matrices, and ...
Cho, Han H.
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