Lemma isapropisEpi {y z : C} (f : y --> z) : isaprop (isEpi f). Proof. apply impred_isaprop; intros t. apply impred_isaprop; intros g. apply impred_isaprop; intros h. apply impred_isaprop; intros H. apply hs. Qed.
Require Import UniMath.Foundations.PartD. Require Import UniMath.Foundations.Propositions. Require Import UniMath.Foundations.Sets. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.NaturalTransformations. Require Import UniMath.CategoryTheory.FunctorCategory. Require Import UniMath.CategoryTheory.Subcategory.Core. Require Import UniMath.CategoryTheory.Core.Functors.