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Comment by martyalain | Hacker News Reader

Every time I try to understand what category theory is, I hit an impassable wall, I don't understand it. Alexander Grothendieck is much too intelligent for me. But I don't despair of getting there one day...

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I've found Bartosz Milewski's lectures on category theory for programmers to be very understandable and enlightening. (And I'm weak on math) He explains it really well in plain terms.

https://www.youtube.com/playlist?list=PLbgaMIhjbmEnaH_LTkxLI...

He also has a series of blog posts on it, but I found the lectures especially helpful.

It's the idea that most structures in math can be put upon a foundation of a structure consisting of objects and the relationships between those objects.

Eugenia Cheng has a couple of very accessible books on Category Theory

I was going to make the same recommendation. In particular I'd recommend her new book, _The Joy of Abstraction_. It's a real textbook that goes up through the Yoneda Lemma, but it isn't too scary and it doesn't assume that the reader already knows any theoretical math.

I read the first couple chapters. It's a bit too watered down in the beginning IMO. I couldn't get past the first part especially when she tries to relate category theory to feminism. Might come back to it later.

As a non-math expert and programmer I highly highly recommend Bartosz stuff I linked it in another branch under my original comment.

Bartosz's material is great but it has a practical programming focus, so Cheng's books which focus more on teach Category Theory as mathematics, make a good complement.

Yeah you're probably right. Ill dive back into her book eventually.

It's mostly the beginning chapters don't even get into the meat of CT quick enough. Instead it spends a lot of time justifying things. I feel It's written for people who hated math even more then I did.

Yes, that book in particular. I have Emily Riehl's Category Theory in Context which was not immediately accessible to me at all. Joy of Abstraction aims to be an on-ramp to that.

I'm not an math expert. I hated math. I learned it off of very informal material:

https://bartoszmilewski.com/2014/10/28/category-theory-for-p...

and his associated youtube videos (which are EVEN better):

https://youtube.com/playlist?list=PLbgaMIhjbmEnaH_LTkxLI7FMa...

Thank you so much for these links, a lot to learn ...

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