A characterezation of regular duo semigroups
A characterization of groups in the class of *-regular semigroups.
A characterization of regular monoids by flatness of left acts.
A class of quasi-adequate transformation semigroups.
A concept of variety for regular biordered sets.
A generalization of the Rees Theorem to a class o£ regular semigroups.
A multiplication of e-varieties of regular -solid semigroups by inverse semigroup varieties
A multiplication of e-varieties of regular -solid semigroups by inverse semigroup varieties is described both semantically and syntactically. The associativity of the multiplication is also proved.
A Note on Classes of Regularity in Semigroups
A note on semilattice decompositions of completely -regular semigroups.
A special congruence lattice of a regular semigroup.
Absolute flatness of regular semigroups with a finite height function.
Abundant semigroups with a medical idempotent.
Adjoint regular rings.
Biregular semigroups. I
Biregular semigroups. II
Certain partial orders on semigroups
Relations introduced by Conrad, Drazin, Hartwig, Mitsch and Nambooripad are discussed on general, regular, completely semisimple and completely regular semigroups. Special properties of these relations as well as possible coincidence of some of them are investigated in some detail. The properties considered are mainly those of being a partial order or compatibility with multiplication. Coincidences of some of these relations are studied mainly on regular and completely regular semigroups.
Characterizations of totally ordered sets by their various endomorphisms
We characterize totally ordered sets within the class of all ordered sets containing at least three-element chains using a simple relationship between their isotone transformations and the so called 2-, 3-, 4-endomorphisms which are introduced in the paper. Another characterization of totally ordered sets within the class of ordered sets of a locally finite height with at least four-element chains in terms of the regular semigroup theory is also given.
Commutativity of Operators on the Lattice of Existence Varieties.
Completely Regular and Orthodox Congruences on Regular Semigroups
Completely regular and orthodox congruences on regular semigroups.