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A First Course in Category Theory

by Jaap van Ooosten

Jaap van Oosten has written a first course in category theory which is intende to contain what's presumed knowledge in not too specialized papers and theses (in computer science). It's 75 pages long. The synopsis is:

  1. Categories and functors. Definitions and examples. Duality.
  2. Natural transformations. Exponents in Cat. Yoneda lemma. Equivalent categories; Set^op equivalent to Complete Atomic Boolean Algebras.
  3. Limits and Colimits. Functors preserving (reflecting) them. (Finitely) complete categories. Limits by products and equalizers.
  4. A little categorical logic. Regular categories, regular epi-mono factorization, subobjects. Interpretation of coherent logic in regular categories. Expressing categorical facts in the logic. Example of \Omega -valued sets for a frame \Omega.
  5. Adjunctions. Examples. (Co)limits as adjoints. Adjoints preserve (co)limits. Adjoint functor theorem.
  6. Monads and Algebras. Examples. Eilenberg Moore and Kleisli as terminal and initial adjunctions inducing a monad. Groups monadic over Set. Lift and Powerset monads and their algebras. Forgetful functor from T-Alg creates limits.
  7. Cartesian closed categories and the \lambda-calculus. Examples of ccc's. Parameter theorem. Typed \lambda calculus and its interpretation in ccc's. Ccc's with natural numbers object: all primitive recursive functions are representable.

The notes are available by anonymous ftp .