Australian Category Seminar

Progress towards semi-strictification for tetracategories

Adrian Miranda·31 August 2022

In previous talks I outlined how strictification in dimensions 2 and 3 can be broken into several steps.

1. Read off generating data (ie a directed graph/2-computad) from the weak-n-category (ie bicategory/tricategory) A.

2. Freely construct the fragment of the semi-strict n category containing only k < n dimensional cells (ie category/sesquicategory).

3. Form a discrete semi-strict n category on that, call it D(A).

4. Pick an arbitrary but consistent way of evaluating n-1 cells.

5. Use the evaluation to form a weak n-functor Ev: D(A) → A.

6. Factorise Ev = F^ B with F fully faithful on n-cells and B bijective on k < n -cells.

This week I will share the progress I have made in executing this program in the case n = 4. Briefly, steps 1, 2, 3, and 4 are done, while steps 5 and 6 need some more work. That being said, I'll also be able to explain some strategies that I've been trying to use to make those steps work.

Back