proposition: Lemma cancel_whisker_left {C : prebicategory} {a b c : C} (f : a -1-> b) {g h : b -1-> c} {alpha alpha': g -2-> h} (p : alpha = alpha') : whisker_left f alpha = whisker_left f alpha'.
proof: Proof. induction p. reflexivity. Defined.
imports: UniMath.Foundations.PartD UniMath.MoreFoundations.Tactics UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.PrecategoryBinProduct UniMath.CategoryTheory.Categories.StandardCategories UniMath.CategoryTheory.HorizontalComposition UniMath.CategoryTheory.Equivalences.Core UniMath.Bicategories.WkCatEnrichment.prebicategory UniMath.Bicategories.WkCatEnrichment.Notations