Results 11 to 20 of about 166 (145)
On semigroups of transformations that preserve a double direction equivalence
Open Mathematics, 2023 For a non-empty set XX, denote the full transformation semigroup on XX by T(X)T\left(X) and suppose that EE is an equivalence relation on XX. Evidently, TE∗(X)={α∈T(X)∣(x,y)∈Eif and only if(xα,yα)∈Efor allx,y∈X}{T}_{{E}^{\ast }}\left(X)=\left\{\alpha \in
Chen Hui, Liu Xin, Wang Shoufeng
doaj +1 more source
Pseudovarieties of Ordered Completely Regular Semigroups [PDF]
Results in Mathematics, 2019 This paper is a contribution to the theory of finite semigroups and their classification in pseudovarieties, which is motivated by its connections with computer science. The question addressed is what role can play the consideration of an order compatible with the semigroup operation.
Jorge Almeida, Ondřej Klíma
openaire +2 more sources
International Journal of Mathematics and Mathematical Sciences, 2018 Let TX be the full transformation semigroup on a set X. For a fixed nonempty subset Y of a set X, let TX,Y be the semigroup consisting of all full transformations from X into Y.
Worachead Sommanee
doaj +1 more source
Canonical Varieties of Completely Regular Semigroups [PDF]
Journal of the Australian Mathematical Society, 2007 AbstractCompletely regular semigroups CR are regarded here as algebras with multiplication and the unary operation of inversion. Their lattice of varieties is denoted by L(CR). Let B denote the variety of bands and L(B) the lattice of its subvarieties. The mapping V → V ∩ B is a complete homomorphism of L(CR) onto L(B). The congruence induced by it has
openaire +2 more sources
Eventually Pointed Principally Ordered Regular Semigroups
Sultan Qaboos University Journal for ScienceAn ordered regular semigroup, , is said to be principally ordered if for every there exists . A principally ordered regular semigroup is pointed if for every element, we have .
G.A. Pinto
doaj +1 more source
Examples and CounterexamplesIn this paper we give an algebraic characterization of assemblies in terms of bands of groups. We also consider substructures and homomorphisms of assemblies. We give many examples and counterexamples.
Ulderico Dardano +2 more
doaj +1 more source
A structure theorem for completely regular semigroups [PDF]
Proceedings of the American Mathematical Society, 1987 Structure theorems for arbitrary completely regular semigroups have been given by Yamada, Warne, Petrich, and Clifford. A new structure theorem for these semigroups is proved here. It is reminiscent of both the structure theorem of Clifford-Petrich and of the Rees construction for completely simple semigroups. It simplicity ought to prove useful in the
openaire +2 more sources
On varieties of completely regular semigroups III
Semigroup Forum, 1985 Completely regular semigroups are semigroups that are unions of their subgroups. They may be regarded as universal algebras with an associative binary multiplication and unary inversion. In this language they form a variety \({\mathcal C}{\mathcal R}\).
openaire +1 more source
A semilattice of varieties of completely regular semigroups [PDF]
Mathematica Bohemica, 2018 A semigroup is completely regular if every element lies in a subgroup. Taking the inverse of each element in a subgroup containing it, completely regular semigroups form a variety of unary semigroups. The paper concerns identifying which subvarieties can be found by starting from two special sets of subvarieties that deserve particular attention.
openaire +3 more sources
A Linear Generalization of the Nearly Gorenstein Property, With Applications to Veronese Subalgebras
Mathematische Nachrichten, EarlyView.ABSTRACT We study the nearly Gorenstein property for Veronese subalgebras of (semi‐)standard graded algebras. We introduce a condition (♮)$(\natural)$ for Cohen–Macaulay semi‐standard graded rings, motivated by the study of Ehrhart rings. We show that if a semi‐standard graded algebra R$ R$ satisfies (♮)$(\natural)$, then its Veronese subalgebras R(k)$
Sora Miyashita
wiley +1 more source