fact: Definition Indirect_Isomorphism_4 {X} `(H : Hom X A ≅ Hom X B) : A ≅ B := Functor_Reflection H.
imports: Ssreflect.choice Basics Endo FCompose Coq.Classes.Morphisms Coq.Setoids.Setoid Coq.Relations.Relation_Definitions