proposition: Lemma EqualizerInsEq {y z: C} {f g : y --> z} (E : Equalizer f g) {w : C} (φ1 φ2: C⟦w, E⟧) (H' : φ1 · (EqualizerArrow E) = φ2 · (EqualizerArrow E)) : φ1 = φ2.
proof: Proof. apply (isEqualizerInsEq (isEqualizer_Equalizer E) _ _ H'). Defined.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Monics UniMath.CategoryTheory.Retracts