Results 101 to 110 of about 136 (128)

Semigroup Rings of Completely Regular Semigroups

1990
A semigroup S is said to be completely regular if and only if it is covered by its subgroups; that is, if and only if, for each a ∈ S, a ∈ a2 S∩S a2. Groups and bands (semigroups of idempotents) are extreme special cases. In this paper a survey is given of results on the Jacobson radical of the semigroup ring of a completely regular semigroup over a ...
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Bases for certain varieties of completely regular semigroups

Commentationes Mathematicae Universitatis Carolinae, 2021
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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Correspondences of completely regular semigroups and -isomorphisms of semigroups

Proceedings of the Royal Society of Edinburgh: Section A Mathematics, 1995
A correspondence of a semigroup S is any subsemigroup of S × S, and the set of all correspondences of S, with the operations of composition and involution and the relation of set-theoretic inclusion, forms the bundle of correspondences of S, denoted by (S).
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Congruences on Completely Regular Semigroups

Canadian Journal of Mathematics, 1989
There are two subjects in the literature on semigroups which have recently attracted great attention: the class of completely regular semigroups (that is semigroups which are unions of their subgroups) and congruences on regular semigroups. In completely regular semigroups, the most popular subject is that of varieties, even though other aspects of ...
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Unification in varieties of completely regular semigroups

1992
All varieties of idempotent semigroups have been classified with respect to the unification types of their defining sets of identities. With the exception of eight finitary unifying theories, they are all of unification type zero. This yields countably many examples of theories of this type which are more “natural” than the first example constructed by
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Ladders and canonical varieties of completely regular semigroups

Periodica Mathematica Hungarica, 2017
The lattice \({\mathcal L} (\mathcal{CR})\) of varieties of completely regular semigroups contains as an ideal the well-studied lattice \({\mathcal{L}} (\mathcal{B})\) of bands. Two associated complete congruences are defined on \({\mathcal L} (\mathcal{CR})\): \(\mathcal{U} \mathrel{\mathbb{B}^{\wedge}} \mathcal{V}\) if \(\mathcal{U} \cap \mathcal{B} =
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Compactness of systems of equations on completely regular semigroups

1997
A semigroup S is said to have the compactness property, or CP for short, if each system of equations over a finite set of variables has an equivalent finite subsystem, that is, having exactly the same solutions in S. We prove that a completely 0-simple semigroup S satisfies CP if and only if the group G in a Rees matrix representation $S = {\mathcal M}^
Tero Harju, Juhani Karhumäki, Mario Petrich   +2 more
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Certain Varieties and Quasivarieties of Completely Regular Semigroups

Canadian Journal of Mathematics, 1977
We adopt the following definition of acompletely regular semigroup S:for every elementaofS,there exists a unique elementa-1ofSsuch ...
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On the structure of semigroups whose regular elements are completely regular

Semigroup Forum, 2023
Xavier Mary
exaly  

On bases of identities of finite central locally orthodox completely regular semigroups

Semigroup Forum, 2021
Jiří Kadourek
exaly