fact: Record adj_morphism {C : Category} {D : Category} := { free_functor : D ⟶ C; forgetful_functor : C ⟶ D; adjunction : free_functor ⊣ forgetful_functor }.
imports: Category.Lib Category.Theory.Category Category.Theory.Isomorphism Category.Theory.Functor Category.Theory.Natural.Transformation Category.Theory.Adjunction Category.Instance.Fun Category.Instance.Sets