4 papers
Free left -Ehresmann semigroups
Daniel Heath
The class of left -adequate semigroups sits between the classes of left ample and left Ehresmann semigroups. Whilst free objects in related classes have descriptions in terms of…
Growth and identities of monogenic free adequate monoids
Thomas Aird, Daniel Heath
Motivated by recent advances in inverse semigroup theory, we investigate the growth of and identities satisfied by free left and free two-sided adequate monoids. We explicitly comp…
A collection of cancellative, singly aligned, non-embeddable monoids
Milo Edwardes, Daniel Heath
By classical results of Malcev, cancellative monoids need not be group-embeddable. In this paper, we describe and give presentations for and study an infinite family $\mathcal{M}_n…
Pretzel monoids
Daniel Heath, Mark Kambites, Nóra Szakács
We introduce an interesting class of left adequate monoids which we call pretzel monoids. These, on the one hand, are monoids of birooted graphs with respect to a natural `glue-and…