proposition: Lemma kelly_left {C : prebicategory} {b c d : C} {g : b -1-> c} {h : c -1-> d} : left_unitor_2mor (g ;1; h) = associator (identity1 b) g h ;v; whisker_right (left_unitor g) h.
proof: Proof. apply whisker_left_id_inj. rewrite whisker_left_on_comp. apply kelly_left_region_1. 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