In this post and the next, I want to try out a new idea and see where it leads. It goes back to where magnitude began, which was the desire to unify elementary counting formulas like the ...

We’re brought up to say that the dual concept of injection is surjection, and of course there’s a perfectly good reason for this. The monics in the category of sets are the injections, the epics are ...

Example Let A be the category (0 → 1) consisting of a single nontrivial map. Then an object of SetobA is a pair (P0, P1) of sets, and an object of SetA is a function X0 f → X1 between a pair of ...

Earlier this month the Mathematics Institute at Uppsala University hosted a conference called Categorification in Algebra and Topology, clearly a theme close to our collective heart. As yet there are ...

This is the homepage for the UT Geometry and Quantum Field Theory Seminar. At the organizational meeting we will flesh out the details of our plans for the semester. Below are some suggestions to get ...

Jan 16, 2025 19:51 Ah, now that’s a very interesting point. Someone who’s fluent in dagger categories would probably have further thoughts about that.

Dec 25, 2024 03:44 Also I thought I should mention that this conversation inspired me to collate my thoughts on some of these mathematical ...

Jan 19, 2025 09:22 Answering as one of the “quiver representation people”: It seems like the cofree representations you are referring to are the ...

Jan 13, 2025 01:49 Also, it seems that you didn’t explicitly show that the existence of identity functions for every set, while in the ...