6 citations · 10 across the 7 of their papers we have counts for
7 papers
Weakly free regular semigroups I. The general case
Luís Oliveira
We prove the existence of a regular semigroup F(X) weakly generated by X such that all other regular semigroups weakly generated by X are homomorphic images of F(X). The semigroup…
Regular semigroups weakly generated by one element
Luís Oliveira
In this paper we study the regular semigroups weakly generated by a single element x, that is, with no proper regular subsemigroup containing x. We show there exists a regular semi…
Regular semigroups weakly generated by idempotents
Luís Oliveira
A regular semigroup is weakly generated by a set X if it has no proper regular subsemigroups containing X. In this paper, we study the regular semigroups weakly generated by idempo…
A combinatorial approach to the structure of locally inverse semigroups
Luís Oliveira
This paper introduces a notion of presentation for locally inverse semigroups and develops a graph structure to describe the elements of locally inverse semigroups given by these p…
A family of varieties of pseudosemilattices
Luis Oliveira
In [3], a basis of identities {u_n = v_n | n\geq 2} for the variety SPS of all strict pseudosemilattices was determined. Each one of these identities u_n = v_n has a peculiar 2-con…
On the variety of strict pseudosemilattices
K. Auinger, L. Oliveira
A new model, in terms of finite bipartite graphs, of the free pseudosemilattice is presented. This will then be used to obtain several results about the variety SPS of all strict p…