fact: Definition yon1 {A : Type} `{Is01Cat A} (a : A) : Fun01 A^op Type := opyon1 (A:=A^op) a.
imports: Basics.Overture Basics.Tactics WildCat.Core WildCat.Equiv WildCat.Universe WildCat.Opposite WildCat.FunctorCat WildCat.NatTrans WildCat.Prod WildCat.ZeroGroupoid