fact: Definition functor_Under_precategories_mor {c c' : C} (h : C⟦c, c'⟧) : functor _ _ := tpair _ _ (is_functor_Under_mor_functor_data h).
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors