Lemma ShortShortExactData_opp_Eq {C : category} {Z : Zero C} (SSED : ShortShortExactData C Z) : Mor1 (MorphismPair_opp SSED) · Mor2 (MorphismPair_opp SSED) = ZeroArrow (Zero_opp C Z) (Ob1 (MorphismPair_opp SSED)) (Ob3 (MorphismPair_opp SSED)). Proof. use (pathscomp0 (@ShortShortExactData_Eq C Z SSED)). rewrite <- ZeroArrow_opp. apply idpath. Qed.
Require Import UniMath.Foundations.PartD. Require Import UniMath.Foundations.Propositions. Require Import UniMath.Foundations.Sets. Require Import UniMath.MoreFoundations.Notations. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.opp_precat. Require Import UniMath.CategoryTheory.Limits.Zero. Require Import UniMath.CategoryTheory.Limits.Opp.