Definition vcomp2_CAT {C D : category} {F G H : [C, D]} : [C,D]⟦F, G⟧ -> [C,D]⟦G, H⟧ -> [C,D]⟦F, H⟧. Proof. intros α β. exact (nat_trans_comp _ _ _ α β). Defined.
Require Import UniMath.Foundations.PartD. Require Import UniMath.MoreFoundations.Tactics. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.NaturalTransformations. Require Import UniMath.CategoryTheory.FunctorCategory. Require Import UniMath.CategoryTheory.whiskering.