On some classes of regular semigroups.
On some finiteness conditions in semigroup and group theory.
On some free semigroups, generated by matrices
Let We call a complex number “semigroup free“ if the semigroup generated by and is free and “free” if the group generated by and is free. First families of semigroup free ’s were described by J. L. Brenner, A. Charnow (1978). In this paper we enlarge the set of known semigroup free ’s. To do it, we use a new version of “Ping-Pong Lemma” for semigroups embeddable in groups. At the end we present most of the known results related to semigroup free and free numbers in a common picture....
On some non-rational congruences on free commutative semigroups.
On some presentations of completely regular semigroups.
On some problems of Petrich concerning Brück and Reilly semigroups.
On some properties of Brandt groupoids.
On some properties of the syntactic semigroup of a very pure subsemigroup
On some subsemigroups of a free semigroup.
On some systems of equations with constraints in a free group. – Addenda. (Sur certains systèmes d'équations avec constraintes dans un groupe libre. – Addenda.)
On some systems of equations with constraints in a free group. (Sur certains systèmes d'équations avec contraintes dans un groupe libre.)
On some type of radicals on a semigroup
On special Qr-filters of semigroups, semirings and rings.
On special Rees matrix semigroups over semigroups
We study the right regular representation of special Rees matrix semigroups over semigroups, and discuss their embedding in idempotent-free left simple semigroups.
On spectra of solvability and attainability for varieties of semigroups.
On strict extensions of semigroups.
On strongly -cyclic acts
By a regular act we mean an act such that all its cyclic subacts are projective. In this paper we introduce strong -cyclic property of acts over monoids which is an extension of regularity and give a classification of monoids by this property of their right (Rees factor) acts.
On strongly reversible semigroups.
On strongly strict extensions of semigroups.
On structure space of -semigroups
In this paper we introduce the notion of the structure space of -semigroups formed by the class of uniformly strongly prime ideals. We also study separation axioms and compactness property in this structure space.