fact: Definition Indirect_Isomorphism_3 `(H : A ≅ B) {X} : Hom X A ≅ Hom X B := Functor_Congruence (Hom X).
imports: Ssreflect.choice Basics Endo FCompose Coq.Classes.Morphisms Coq.Setoids.Setoid Coq.Relations.Relation_Definitions