[xjm]

Nice!

Note that this page has no category theory yet since it explains sets, so if you already know sets, set product, etc and want to learn about category theory, my advice is to go directly to the next chapter, more specifically to this section:

https://abuseofnotation.github.io/category-theory-illustrate...

which uses set theory terms to define the category theory way of defining products (the corresponding "universal property").

[munchler]

I really like this approach, but it contains some confusing mistakes. For example, unless I'm very much mistaken, the illustration of the initial object is backwards: https://abuseofnotation.github.io/category-theory-illustrate...

[slacka]

The author said he is just starting on the book, so he's not claiming it's perfect. And the beauty of github, open source is you can fix them with a pull request. For example, the svg is here: https://github.com/abuseofnotation/category-theory-illustrat...

[JadeNB]

> For example, unless I'm very much mistaken, the illustration of the initial object is backwards: https://abuseofnotation.github.io/category-theory-illustrate...

You are right. (Curiously, the picture of the terminal object is correct, so they didn't just switch them!)

[haskman]

Looks fine to me. What's wrong with it?

[boris_m]

Author here. It was backwards, I fixed it when I saw the comment. Feel free to report any other mistakes you see on https://github.com/abuseofnotation/category-theory-illustrat... or email.

[haskman]

Seems you might have fixed it before I saw it! Thanks!