Congruences on an ample semigroup S are investigated. For any admissible congruence ρ
ρ on S, the minimum σ _ ρ σ ρ (the maximum μ _ ρ μ ρ) admissible congruence on S whose …

We ascertain conditions and structures on categories and semigroups which admit the
construction of pseudo-products and trace products respectively, making their connection as …

We give a construction of the projective indecomposable modules and a description of the
quiver for a large class of monoid algebras including the algebra of any finite monoid whose …

We consider the question of membership of A∨ G, where A and G are the pseudovarieties
of finite aperiodic semigroups, and finite groups, respectively. We find a straightforward …

The construction by Hall of a fundamental orthodox semigroup WB from a band B provides
an important tool in the study of orthodox semigroups. We present here a semigroup SB that …

The class of P-Ehresmann semigroups has been proposed by Jones as a common
generalization of the classes of Ehresmann semigroups and regular∗-semigroups, and the …

The investigation of orthodox P-restriction semigroups was initiated by Jones in 2014 as
generalizations of orthodox*-semigroups. The aim of this paper is to further study orthodox P …

An orthogroup is a completely regular orthodox semigroup. The main purpose of this paper
is to find a representation of a (generalised) orthogroup with band of idempotents B in terms …

I give a historical survey of the three main approaches to the study of the structure of inverse
semigroups. Â The first is that via\emph {inductive groupoids}, as studied by Charles …

The topic of this thesis is the class of weakly U-abundant semigroups. This class is very
wide, containing inverse, orthodox, regular, ample, adequate, quasi-adequate, concordant …