proposition: Lemma is_nat_trans_horcomp : is_nat_trans _ _ horcomp_data.
proof: Proof. intros c d f; unfold horcomp_data; simpl. rewrite assoc, nat_trans_ax, <- !assoc; apply maponpaths. now rewrite <- !functor_comp, nat_trans_ax. Qed.
imports: UniMath.Foundations.PartD UniMath.MoreFoundations.Tactics UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.whiskering UniMath.CategoryTheory.PrecategoryBinProduct UniMath.CategoryTheory.FunctorCategory UniMath.CategoryTheory.UnitorsAndAssociatorsForEndofunctors