Lemma FiberExt_Comm3 {C1 C2 : Complex A} (f g : Morphism C1 C2) (H : ComplexHomot A C1 C2) (Comm : to_binop _ _ ((f : (ComplexPreCat_Additive A)⟦_, _⟧)) (to_inv ((g : (ComplexPreCat_Additive A)⟦_, _⟧))) = ComplexHomotMorphism A H) : ((MappingConePr1 A f) : (ComplexPreCat_Additive A)⟦_, _⟧) = ((FiberExt f g H Comm) : (ComplexPreCat_Additive A)⟦_, _⟧) · (MappingConePr1 A g). Proof. use MorphismEq. intros i. cbn. unfold FiberExtMor. set (DS1 := to_BinDirectSums A (C1 (i + 1)) (C2 i)). set (DS2 := to_BinDirectSums A (C1 (i + 1 + 1)) (C2 (i + 1))). rewrite to_postmor_linear'. rewrite to_postmor_linear'. rewrite <- assoc. rewrite <- assoc. rewrite <- assoc. rewrite <- assoc. rewrite (to_IdIn1 DS1). rewrite (to_Unel2' DS1). rewrite id_right. rewrite ZeroArrow_comp_right. rewrite ZeroArrow_comp_right. rewrite ZeroArrow_comp_right. rewrite to_lunax''. rewrite to_runax''. apply idpath. Qed.
Require Import UniMath.Foundations.UnivalenceAxiom. Require Import UniMath.Foundations.PartD. Require Import UniMath.Foundations.Propositions. Require Import UniMath.Foundations.Sets. Require Import UniMath.Foundations.NaturalNumbers. Require Import UniMath.MoreFoundations.PartA. Require Import UniMath.Algebra.BinaryOperations. 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.TransportMorphisms. 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.Pushouts. Require Import UniMath.CategoryTheory.Limits.Pullbacks. Require Import UniMath.CategoryTheory.Limits.BinDirectSums. Require Import UniMath.CategoryTheory.Monics. Require Import UniMath.CategoryTheory.Epis. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Adjunctions.Core. Require Import UniMath.CategoryTheory.Equivalences.Core. 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.AbelianToAdditive. Require Import UniMath.CategoryTheory.AdditiveFunctors. Require Import UniMath.HomologicalAlgebra.Complexes. Require Import UniMath.HomologicalAlgebra.KA. Require Import UniMath.HomologicalAlgebra.TranslationFunctors.