Some Categorical Concepts

Abstract

We will assume that the reader has a certain degree of familiarity with the general theory of categories. However, in order to provide some easily available references and at the same time to simplify certain future proofs, in this chapter we will recall those categorical concepts and results that will be frequently used throughout the book. Since it is not our intention to provide a complete treatment of the included topics, many of the details will be left as exercises. The reader who wants a deeper insight into the topics of this chapter should consult a book on the theory of categories and in particular we suggest [AHS], [HS] and [M]. We also recommend these books for all those other concepts that are not mentioned in this chapter since they only sporadically appear in the book.