U. Haifa Topology & Geometry seminar: Sunday, July 24, 2022. Speaker: Simona Paoli (Aberdeen). Title: “Weakly globular double categories and weak units”.

Time:         17:00 (Israel Time)

Location:  Room 614 of the Science & Education Building, University of Haifa and on Zoom

Recording link:


Segal-type models of weak 2-categories are simplicial models of bicategories, and they comprise the Tamsamani model and the more recent weakly globular double categories. Fair 2-categories, introduced by J. Kock, model weak 2-categories with strictly associative compositions and weak unit laws. This model has some features in common with the Segal-type models, but with the simplicial delta replaced by the fat delta, which encodes weak units.   

I will illustrate a direct comparison of fair 2-categories with the Segal type models: this result sheds new light on the notion of weak globularity as encoding weak units and has potential for higher dimensional generalizations.