fact: Definition yon_equiv {A : Type} `{HasEquivs A} `{!Is1Cat_Strong A} (a b : A) : (yon1 a $<~> yon1 b) -> (a $<~> b) := opyon_equiv (A:=A^op).
imports: Basics.Overture Basics.Tactics WildCat.Core WildCat.Equiv WildCat.Universe WildCat.Opposite WildCat.FunctorCat WildCat.NatTrans WildCat.Prod WildCat.ZeroGroupoid