Coverings and liftings of generalized crossed modules

Crossed modules are algebraic structures that have applications in many fields of mathematics and physics. In the literature, crossed modules have been defined for almost all algebraic structures and various properties related to them have been investigated. Covering concept, which is an important concept in topological spaces, has also been defined for crossed modules and various categorical equivalences have been obtained. The concept of lifting of crossed modules has recently emerged. The generalized crossed module definition is obtained by taking arbitrary actions instead of conjugation actions in the definition of crossed modules. In this thesis, as the main goal, the concepts of cover and elevation in the category of generalized crossed modules were defined and a categorical equivalence similar to the one in the literature was obtained. This thesis consists of six chapters. In the first chapter, information about the history of the subject is given. In the second part, the basic concepts that will be used in the rest of the thesis are given. In the third chapter, the generalized crossed module concept is reminded and the generalized cat1-group concept is defined by using similar thinking. In the fourth chapter, the concept of cover in generalized crossed modules is defined and various properties are examined. In the fifth chapter, the concept of elevation in generalized crossed modules is defined and its various properties are examined. Finally, in the sixth section, the results obtained are interpreted and the studies that can be done afterwards are mentioned.