This project aims are the following: To investigate topological properties of the Brandt lambda^0-extension, especially the preserving of the minimality, and discovering the minimal semigroup topologies on it. To establish or, at least, to approach the criteria on different classes of topological semigroups to be H-closed (absolutely H-closed), thus solving one of the main problems in the theory of topological semigroups. On that way, we plan to solve Stepp Problem about H-closed semilattices in some classes of topological semilattices. One of the most important goals is to find new classes of H-closed semigroups. For that purpose we need to investigate the H-closedness and absolute H-closedness properties of the semigroup of finite partial bijection of a bounded rank I^lambda_n as topological inverse semigroups. Proceeding investigations in the direction of finding structural theorems for the classes of simple and bisimple omega–semigroups, we wish to construct a generalization of the bicyclic extensions and study the algebraic properties and topologizations of the extensions. Also topological and algebraic properties of the extensions, which are preserved by functors of embedding in the categories of algebraic and topological semigroups, will be investigated. The structure of other topologico-algebraic extensions of topological semigroups, such as topological extensions of nilpotent generated semigroup extensions will be investigated. There is a reason to believe that this will lead to an interesting new class of semigroups. We also wish to find such bisimple inverse semigroups with a singleton Green H-classes which can be described as a Zappa-Szép square of the free monoids with a one generate element. Besides, the project aims application of the obtained results in universal algebras, automata theory, and exchange of experience.