Thoughts on Quantitative Type Theory

September 25, 2022 Brad Venner

Jacques Carette’s YouTube lecture on what he learned about category theory by formalizing it in Agda, which is based on Martin-Lof type theory, was (recommended)[https://twitter.com/bgavran3/status/1573263845044506625] by Bruno Gavranovic on Twitter.

Carette uses setoids in their formulation of category theory, so that technically the formulation is of setoid-enriched category theory. The additional level of an equivalence relation over the hom-set of morphisms. Carette refers to this model as a 3/2 category due to the addition level on the set of morphisms that resembles a natural transformation. The three levels of objects, hom-sets and equivalence relations are all given type “universes” in the model.