Schreier Extensions of Topological Semigroups.
John Ganci · 1975
The notion of Schreier extensions of groups has been generalized to extensions of semigroups.We review the main results about extensions of semigroups, and we then study the group of units and the minimal ideal of an extension.Some examples are presented that illustrate the propositions.In order, to study extensions of topological semigroups it is necessary to introduce the notion of a semigroup bundle, analogous to the notion of a group bundle.A functorial connection between semigroup bundles and group bundles is constructed that allows one to apply the welldeveloped theory of group bundles to semigroup bundles.Before proceeding to extensions of topological semigroups, we develop some of the topological properties of semigroup bundles.The definition of a Schreier extension of a topo logical semigroup combines the two notions of extensions of