A unified syntactical approach to theorems of Putcha, Margolis, and Straubing on finite power semigroups.
A uniform chain whose inverse semigroup has no chart.
Abundant semigroups whose idempotents satisfy permutation identities.
Abundant semigroups with a medical idempotent.
Abundant semigroups with a multiplicative type A transversal.
Addendum to: Representations of inverse semigroups by one-to-one partial transformations of a set.
Algebraic analysis in structures with the Kaplansky-Jacobson property
In 1950 N. Jacobson proved that if u is an element of a ring with unit such that u has more than one right inverse, then it has infinitely many right inverses. He also mentioned that I. Kaplansky proved this in another way. Recently, K. P. Shum and Y. Q. Gao gave a new (non-constructive) proof of the Kaplansky-Jacobson theorem for monoids admitting a ring structure. We generalize that theorem to monoids without any ring structure and we show the consequences of the generalized Kaplansky-Jacobson...
Algebraic approach to locally finite trees with one end
Let be an infinite locally finite tree. We say that has exactly one end, if in any two one-way infinite paths have a common rest (infinite subpath). The paper describes the structure of such trees and tries to formalize it by algebraic means, namely by means of acyclic monounary algebras or tree semilattices. In these algebraic structures the homomorpisms and direct products are considered and investigated with the aim of showing, whether they give algebras with the required properties. At...
Algebraic monoids with a dense group of units.
Algebras of multiplace functions.
Algebras, prerings, semirings and rectangular bands.
Algèbres de demigroupes, quotients d'algebres de demigroupes finis.
All varieties of orthogroups.
An analogue of Litoff's Theorem.
An easy proof of Ponizovski's theorem.
An embedding theorem for weakly inverse semigroups.
An equivalence theorem for inverse semigroups.
An order theoretic characterization of locally orthodox regular semigroups.
Another proof of a theorem of Evans.
Anti-Inverse Semigroups