Category Theory

An accessible introduction to category theory at the undergraduate level, with an emphasis on various specific categories of mathematical structures, including the following topics: Structured sets and their morphisms, including examples such as ordered sets, lattices, graphs, monoids, groups, and rings; categories; various examples of categories; products, equalizers, coproducts, and coequalizers, with examples in specific categories; functors, with various examples; natural transformations; universal arrows, with various examples such as free monoids and free semilattices; adjunctions; equivalence of categories