[Haskell] Math behind Haskell

[Tomas Caithaml]

Hi all.

When I was playing with Haskell and reading stuff about it, I noticed
that there is a lot of information in a form of research papers and a
lot of mathematics involved. I must confess that I quite like this
academic approach.

Well, I thought that while I am still at university I could take some
math classes to help me better understand these things and 
broaden my horizon.

Any suggestion what could be relevant?

I came up with:

 * Lambda calculus - the basis of functional languages

 * Category theory - where all these mysterious things like monads,
arrows, and functors come from.

 * Topology (?) - don't know; I thought it is important rather in
mathematical analysis (which I don't like much) but I have seen
somewhere some references to it in context of CS.

Any other suggestions?

Thanks, Tom.