On semidirect products of quantale enriched monoids

Abstract

We consider monoids equipped with a compatible quantale valued relation, to which we call quantale enriched monoids, and study semidirect products of such structures. It is well-known that semidirect products of monoids are closely related to Schreier split extensions which, in the setting of monoids, play the role of split extensions of groups. We will thus introduce certain split extensions of quantale enriched monoids, which generalize the classical Schreier split extensions of monoids, and investigate their connections with semidirect products. We then restrict our study to a class of quantale enriched monoids whose behavior mimics the fact that the preorder on a preordered group is completely determined by its cone of positive elements. Finally, we instantiate our results for preordered monoids and compare them with existing literature.