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Patrick Nicodemus (May 30 2026 at 01:55):In the "unified theory of generalized multicategories" paper by cruttwell and shulman it is claimed that if a virtual double category has all units then for any vertical 1-cell f there is an associated 2-cell U_f between the horizontal units. How is this defined?
Patrick Nicodemus (May 30 2026 at 02:11):It must be some kind of creative appeal to the definition of opcartesian but I don't get it
Evan Patterson (May 30 2026 at 03:29):I got tripped up on this once myself. The answer is in this thread.
Patrick Nicodemus (May 30 2026 at 11:39):Nullary composition of two cells. Ahhh.