The aim of this paper is to study DRC-semigroups by “categorial approach” and give an
Ehresmann–Schein–Nambooripad type theorem (ESN type theorem for short) for this class …

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

Demonic composition, demonic refinement and demonic union are alternatives to the usual
'angelic'composition, angelic refinement (inclusion) and angelic (usual) union defined on …

In a result generalising the Ehresmann–Schein–Nambooripad Theorem relating inverse
semigroups to inductive groupoids, Lawson has shown that Ehresmann semigroups …

Motivated by the demonic compositions of binary relations, Stokes has introduced
demigroups (that is, d-semigroups in our terminology) and shown that many well known …

Demonic composition is defined on the set of binary relations over the non-empty set X,
Rel_X R el X, and is a variant of standard or “angelic” composition. It arises naturally in the …

Given a monoid S with E any non-empty subset of its idempotents, we present a novel one-
sided version of idempotent completion we call left E-completion. In general, the …

Constellations are asymmetric generalisations of categories. Although they are not required
to possess a notion of range, many natural examples do. These include commonly occurring …

We give an algebraic characterisation of ordered groupoids, namely, we show that there is a
categorical isomophism between the category of ordered groupoids and the category of $ D …

Demonic composition*∗ is an associative operation on binary relations, and demonic
refinement ⊑⊑ is a partial order on binary relations. Other operations on binary relations …