In this paper we develop a new groupoid-based structure theory for the class of regular⁎-
semigroups. This class occupies something of a 'sweet spot'between the important classes …

Lawson has obtained an Ehresmann–Schein–Nambooripad theorem (ESN theorem for
short) for Ehresmann semigroups which states that the category of Ehresmann semigroups …

The main goal of this article is to unite the theories of groupoids, semigroups and their
dynamical aspects under a unique umbrella theory, which is attained with semigroupoids …

In this paper we provide a theory of chain projection ordered categories and generalize that
of chain projection ordered groupoids developed by East and Azeef Muhammed recently. By …

We prove a generalisation of the correspondence, due to Resende and Lawson–Lenz,
between étale groupoids—which are topological groupoids whose source map is a local …

In this work we introduce partial and global actions of inverse categories on posets in two
variants, fibred actions and actions by symmetries. We study in detail actions of an inverse …

Group theory and group actions are classical mathematical objects of study. The abstract
concept of a group and the role that group actions play are well established and have many …

In this paper we introduce a description of ordered groupoids as a particular type of double
categories. This enables us to turn Lawson's correspondence between ordered groupoids …

We show that there is a one-to-one correspondence between the partial actions of a
groupoid $ G $ on a set $ X $ and the inverse semigroupoid actions of the Exel's inverse …

Provamos que existe uma correspondência um para um entre as ações parciais de um
grupoide G sobre um conjunto X e as ações de semigrupoide inverso do semigrupoide …