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Comment by frak_your_couch | Hacker News Reader

Any suggestions for a good Category Theory texts that're oriented to CS and go beyond the "classical" connections between cartesian closed categories and lambda calculi? Or am I stuck in another frustrating 2-week long session trying to divine "Category Theory for the working mathematician" and a hand-full of research papers and blogs on Haskell?

Edit: Sorry if I sound bitter, but I've been down the category theory route multiple times in the past, starting in graduate school (in Math) and I've always given up before I "got" the divine revelation that others have talked about.

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I don't think there is anything particularly brilliant.

There's Category Theory for Computing Science by Barr and Wells (http://www.case.edu/artsci/math/wells/pub/ctcs.html), which is a good enough book but hardly comprehensive.

I don't know any way round the fact that category theory is difficult to learn. I think that's partly inherent in the subject, not helped by the lack of a really good textbook suitable for beginners.

(Here is the totality of my published work in category theory: http://arxiv.org/pdf/math/0604542v3)

Yeah, I came across Barr and Wells 5 years ago in grad school and found it almost impossible to buy. I ended up getting a copy from the library and photocopying and rebinding it. Like you said, it was ok, but hardly comprehensive. Maybe it's easier to find now.

Anyway, nice paper..and thanks for making me think of category theory again. Maybe I'll pull out my old copy of "CT for the working mathematician" and give it (and haskell) another go.

Edit: I came across this: http://www.amazon.com/gp/product/0521422264/ref=pd_lpo_k2_dp...

Anyone gone through this book?

I think you can buy the Barr and Wells book via the web page I gave. In fact I think that's how I got my copy, which must have been around the same time you were looking for it.

I haven't read Walters book, & would also be interested to hear reactions from anyone here who has.

Because it was not mentioned until now, one of the following might probably come in handy:

- Basic Category Theory for Computer Scientists by Benjamin C. Pierce (from "Types and Programming Languages" fame)

- Practical Foundations of Mathematics, by Paul Taylor (has other interesting work on his homepage as well; http://www.paultaylor.eu/~pt/prafm/; somebody on HN pointed me to it, thanks!--Chapters 4,5,7)

I came across a set of videos in YouTube on Category Theory (can't remember if I found it on HN itself).

Here's the link: http://www.youtube.com/user/TheCatsters

While browsing for related source after making my post I found this site:

http://tunes.org/wiki/category_20theory_20101.html

I liked their explanations of algebras and coalgebras.

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