Lemma abgr_epi_cokernel_isCokernel_uniqueness {A B C : abgr} (f : abgr_category⟦A, B⟧) (isE : isEpi f) (h : abgr_category⟦A, C⟧) (H : KernelArrow (abgr_Kernel f) · h = ZeroArrow abgr_Zero (abgr_Kernel f) C) (t : ∑ ψ : abgr_category ⟦B, C⟧, f · ψ = h) : t = make_abgr_epi_cokernel_isCokernel f isE h H. Proof. use total2_paths_f. - use isE. use (pathscomp0 (pr2 t)). use monoidfun_paths. use funextfun. intros x. exact (pr2 (iscontrpr1 (abgr_epi_CokernelOut_iscontr f isE h H (pr1 f x))) (@make_hfiber _ _ (pr1 f) (pr1 f x) x (idpath _))). - use proofirrelevance. use setproperty. Qed.
Require Import UniMath.Foundations.PartD. Require Import UniMath.Foundations.Propositions. Require Import UniMath.Foundations.Sets. Require Import UniMath.Foundations.UnivalenceAxiom. Require Import UniMath.Algebra.BinaryOperations. Require Import UniMath.Algebra.Groups. Require Import UniMath.Algebra.Monoids. Require Import UniMath.NumberSystems.Integers. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.Univalence. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Monics. Require Import UniMath.CategoryTheory.Epis. Require Import UniMath.CategoryTheory.CategoriesWithBinOps. Require Import UniMath.CategoryTheory.PrecategoriesWithAbgrops. Require Import UniMath.CategoryTheory.PreAdditive. Require Import UniMath.CategoryTheory.Additive. Require Import UniMath.CategoryTheory.Abelian. Require Import UniMath.CategoryTheory.Limits.Zero. Require Import UniMath.CategoryTheory.Limits.BinProducts. Require Import UniMath.CategoryTheory.Limits.BinCoproducts. Require Import UniMath.CategoryTheory.Limits.Equalizers. Require Import UniMath.CategoryTheory.Limits.Coequalizers. Require Import UniMath.CategoryTheory.Limits.Kernels. Require Import UniMath.CategoryTheory.Limits.Cokernels. Require Import UniMath.CategoryTheory.Limits.BinDirectSums. @ZeroArrowFrom abgr_category abgr_Zero A = abgrfunfromunit A.