proposition: Lemma is_nat_trans_pre_whisker (A B C : precategory_data) (F : functor_data A B) (G H : functor_data B C) (gamma : nat_trans G H) : is_nat_trans (functor_composite_data F G) (functor_composite_data F H) (λ a : A, gamma (F a)).
proof: Proof. intros a b f; simpl. apply nat_trans_ax. Qed.
imports: UniMath.Foundations.PartD UniMath.Foundations.Propositions UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.FunctorCategory