Astro Hacker News - How to prove equations using diagrams, part 1

henearkr |next [-]

Very interesting!!

A nitpick, for a J-shaped diagram D, J is the "index category" or the "scheme" of D, not the "shape" like written in the article.

epatters |root |parent |next [-]

Thanks!

Yes, there are lots of different names for the domain of a diagram, but "shape" is a common enough one. You can find it in standard sources, including the nLab [1] and some textbooks.

[1] <https://ncatlab.org/nlab/show/diagram>

henearkr |root |parent [-]

Ah you're right!

My bad for not keeping up.

JadeNB |root |parent |previous [-]

The article does mention "index[ing] category." I think terminology here is not especially universal: I am a mathematician but not a category theorist, and I have seen "shape" but not "scheme."

henearkr |root |parent [-]

Yes, it is completely understandable with "shape".

As I am not a professional mathematician, I have read a very limited number of books touching the subject, so my vocabulary was in fact a bit too narrow. I should have looked up on nLab before making a fool of myself.

JadeNB |root |parent [-]

Don't be hard on yourself. It was a perfectly reasonable and polite comment.

boldslogan |next |previous [-]

man ive recently stumbled on this concept of functor or nonsymbolic logic and such. don't suppose you have any suggestions to look at?

fn-mote |previous [-]

This is a category theory post. The subtitle is “initial functors”.

Now you can save yourself a click.