fact: Definition natequiv_yon_equiv {A : Type} `{HasEquivs A} `{!HasMorExt A} (a b : A) : (a $<~> b) -> (yon1 a $<~> yon1 b) := natequiv_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