A Gentle Introduction to Category Theory Lecture notes by Maarten M. Fokkinga introducing some important notions from category theory, in particular adjunctions. Proofs are given in a calculational style, and the (few) examples are taken from algorithmics. The text is a long PostScript file.
Computational Category Theory An implementation of concepts and constructions from category theory in the functional programming language Standard ML. Documentation and code.
CT Category Theory Section of the e-print arXiv dealing with category theory, including such topics as: enriched categories, topoi, abelian categories, monoidal categories, homological algebra.
Structure Theorists List of logicians, algebraists, categoricians, ... working on mathematical structure.
Structures Directory Email directory of logicians, algebraists, and programming linguists working primarily on structural problems in mathematics and computer science.
Taylor, Paul Queen Mary and Westfield College, London - Foundations of Mathematics and Computation.
The Computational Category Theory Project The aim of the project is the development of software on a wide variety of platforms for computing with mathematical categories and associated algebraic structures.
Toposes, Triples and Theories By Michael Barr and Charles Wells, 1983. A revised and corrected version is now available free for downloading. Formats: DVI, PDF, PostScript.
