proposition: Lemma transport_source_isEpi {x y z : C} (f : y --> z) (E : isEpi f) (e : y = x) : isEpi (transportf (λ x' : ob C, precategory_morphisms x' z) e f).
proof: Proof. induction e. apply E. Qed.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.FunctorCategory UniMath.CategoryTheory.Subcategory.Core UniMath.CategoryTheory.Core.Functors