Spined products of some semigroups

Semidirect Products of Ordered Semigroups

Semidirect Products of Ordered Semigroups

Semidirect products of ordered semigroups

We introduce semidirect and wreath products of finite ordered semigroups and extend some standard decomposition results to this case.

Semidirect Products of Regular Semigroups

Within the usual semidirect product S ∗ T of regular semigroups S and T lies the set Reg (S ∗ T ) of its regular elements. Whenever S or T is completely simple, Reg (S ∗T ) is a (regular) subsemigroup. It is this ‘product’ that is the theme of the paper. It is best studied within the framework of existence (or e-) varieties of regular semigroups. Given two such classes, U and V, the e-variety U...

Set products in transformation semigroups

We describe products of arbitrary L, R, and H-classes with the set of idempotents of full transformation semigroups.