Definition CokernelEpiComp_mor1 {x y z : C} (E : Epi C x y) (f : y --> z) (CK1 : Cokernel Z (E · f)) (CK2 : Cokernel Z f) : C⟦CK1, CK2⟧ := CokernelOut Z CK1 _ (CokernelArrow CK2) (CokernelEpiComp_eq1 E f CK1 CK2).
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.Epis. Require Import UniMath.CategoryTheory.Limits.Coequalizers. Require Import UniMath.CategoryTheory.Limits.Zero. - exact (ZeroArrowFrom w). - intros y X. cbn in X. use ArrowsFromZero.