Definition rassociator_CAT {C D E F : category} (X : [C, D]) (Y : [D, E]) (Z : [E, F]) : [C, F] ⟦functor_compose (functor_compose X Y) Z, functor_compose X (functor_compose Y Z)⟧ := nat_trans_id (functor_composite (functor_composite X Y) Z).
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.