proposition: Lemma hcomp_identity_left {a b c : C} (f : C ⟦ a, b ⟧)(g1 g2 : C ⟦ b, c ⟧) (y : g1 ==> g2) : id2 f ⋆ y = lwhisker f y.
proof: Proof. unfold hcomp. rewrite id2_rwhisker. apply id2_left. Qed.
imports: UniMath.Tactics.EnsureStructuredProofs UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.PrecategoryBinProduct