proposition: Lemma rwhisker_lwhisker_rassociator_CAT {A B C D : category} {F : [A, B]} {G H : [B, C]} {I : [C, D]} (α : [B, C]⟦G, H⟧) : rassociator_CAT _ _ _ · lwhisker_CAT F (rwhisker_CAT I α) = rwhisker_CAT I (lwhisker_CAT F α) · rassociator_CAT _ _ _.
proof: Proof. apply (nat_trans_eq D); intro c. cbn. rewrite id_right; apply id_left. Qed.
imports: UniMath.Foundations.PartD UniMath.MoreFoundations.Tactics UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.FunctorCategory UniMath.CategoryTheory.whiskering