proposition: Lemma EqualizerKernel_eq {x y : ob C} {f : x --> y} (E : Equalizer f (ZeroArrow Z _ _)) : EqualizerArrow E · f = ZeroArrow Z E y.
proof: Proof. rewrite <- (ZeroArrow_comp_right _ _ _ _ _ (EqualizerArrow E)). exact (EqualizerEqAr E). Qed.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Monics UniMath.CategoryTheory.Limits.Equalizers UniMath.CategoryTheory.Limits.Zero