Pacific Category Theory Seminar
The Pacific Category Theory (PCT) seminar is an online seminar for the category theory community in the Asia-Pacific time zone and beyond. We aim to cover topics in all areas of pure and applied category theory in relationship with other disciplines.
The seminar will run once or twice a month on Friday at 10am JST/12pm AED (1am UTC). Here is the zoom link to partipate. Previous talks are available on the seminar's youtube channel.
Upcoming talks
February 27, 2026
- Speaker: Yuki Imamura (RIMS, Kyoto University)
March 20, 2026 (TBC)
- Speaker: Dusko Pavlovic (University of Hawaii)
Previous talks
January 16, 2026
- Speaker: Taichi Uemura (Nagoya University)
Title: A direct-categorical approach to opetopic sets and opetopes
Abstract: Opetopes and opetopic sets were introduced by Baez and Dolan as a combinatorial approach to weak ω-categories. Since its birth, several equivalent definitions have been proposed.
Recently, Leclerc gave a posetal definition of opetopes, where an opetope is encoded as a poset of cells ordered by the subcell relation. This seems to be the most elementary and simple definition of opetopes, but there is some complication related to loops.
In this talk, I propose another elementary definition of opetopes, encoding an opetope as a direct category rather than a poset. Loop issues are resolved by allowing distinct parallel morphisms, and the theory of opetopic sets gets simplified.
Recording and slides
December 12, 2025
- Speaker: Richard Garner (Macquarie University)
Title: Universal enrichments
Abstract: For a given category C, there are all sorts of things we might enrich it in. For example, the category of complex vector spaces can be enriched in commutative monoids, or abelian groups, or real vector spaces, or complex vector spaces. In this talk, we explain how, for any locally presentable category C, there is a universal locally presentable monoidal category V in which it can be enriched. The fun part is trying to calculate V for particular choices of C; in general, it is rather intractable but sometimes we get lucky!
Recording and slides