proposition: Lemma CoequalizerCokernel_eq {x y : ob C} {f : x --> y} (CE : Coequalizer f (ZeroArrow Z _ _)) : f · CoequalizerArrow CE = ZeroArrow Z x CE.
proof: Proof. rewrite <- (ZeroArrow_comp_left _ _ _ _ _ (CoequalizerArrow CE)). exact (CoequalizerEqAr CE). Qed.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Epis UniMath.CategoryTheory.Limits.Coequalizers UniMath.CategoryTheory.Limits.Zero