4 papers · 1 filter
On the normality of monoid monomorphisms
Nelson Martins-Ferreira, Manuela Sobral
In the category of monoids we characterize monomorphisms that are normal, in an appropriate sense, to internal reflexive relations, preorders or equivalence relations. The zero-cla…
Schreier split extensions of preordered monoids
Nelson Martins-Ferreira, Manuela Sobral
Properties of preordered monoids are investigated and important subclasses of such structures are studied. The corresponding full subcategories of the category of preordered monoid…
Split extensions and semidirect products of unitary magmas
Marino Gran, George Janelidze, Manuela Sobral
We develop a theory of split extensions of unitary magmas, which includes defining such extensions and describing them via suitably defined semidirect product, yielding an equivale…
Cancellative conjugation semigroups and monoids
A. P. Garrão, N. Martins-Ferreira, M. Raposo +1
We show that the category of cancellative conjugation semigroups is weakly Mal'tsev and give a characterization of all admissible diagrams there. In the category of cancellative co…