arXiv subjects
Publications and source records attributed to Nasir Sohail.
The problem of embedding an ample semigroup in an inverse semigroup as a (2, 1, 1)-type subalgebra is known to be undecidable. In this article, we investigate the problem for certain classes of ample semigroups. We also give examples of semigroups that are left (respectively, right) but not right (respectively, left) ample.
A semigroup amalgam (S; T1, T2) is known to be non-embeddable if T1 and T2 are both groups (completely regular semigroups, Clifford semigroups) but S is not such. We prove some non-embeddability conditions for semigroup amalgams (S; T1, T2) in which T1 and T2 are inverse semigroups but S is not such. We also introduce some sufficient conditions that make the inverse hulls of the copies of S in T1 and T2 isomorphic; making, in turn, the amalgam (S; T1, T2) weakly embeddable.
We prove that epimorphisms are surjective in certain categories of ordered F-algebras. It then turns out that epimorphisms are also surjective in the category of all (unordered) algebras of type F.