Hi! I bet there's a lot of great applications of category theory to linear programming or convex programming. They're the sort of mathematical subject that lends itself to category theory. Unfortunately I don't know exactly what to try first.
The forum is not very active now, but you can still get a lot out of it by starting the course here:
* [[Applied Category Theory Course]].
You'll see 77 "lectures" on Fong and Spivak's book (which is free online), and lots of solved exercises, and lots of discussion. You can ask questions on these lectures, but I'm busy enough that I don't promise to answer them! If you want to grab my attention, you can post a comment on the Azimuth Blog, for example here:
* [Applied Category Theory Seminar](https://johncarlosbaez.wordpress.com/2018/12/14/applied-category-theory-seminar/).
This post is about the seminar we're currently running at UCR, which has videos and such.