THE WREATH PRODUCT PRINCIPLE FOR ORDERED SEMIGROUPS

The wreath product principle for ordered semigroups

Straubing’s wreath product principle provides a description of the languages recognized by the wreath product of two monoids. A similar principle for ordered semigroups is given in this paper. Applications to language theory extend standard results of the theory of varieties to positive varieties. They include a characterization of positive locally testable languages and syntactic descriptions ...

Wreath Product Decompositions for Triangular Matrix Semigroups

We consider wreath product decompositions for semigroups of triangular matrices. We exhibit an explicit wreath product decomposition for the semigroup of all n× n upper triangular matrices over a given field k, in terms of aperiodic semigroups and affine groups over k. In the case that k is finite this decomposition is optimal, in the sense that the number of group terms is equal to the group c...

An Extension of the Wreath Product Principle for Nite Mazurkiewicz Traces

Semidirect Product Decompositions of Ordered Groupoids and Inverse Semigroups

Ordered Categories and Ordered Semigroups