Definition is_nat_trans {C C' : precategory_data} (F F' : functor_data C C') (t : nat_trans_data F F') := ∏ (x x' : ob C)(f : x --> x'), # F f · t x' = t x · #F' f.
Require Import UniMath.Foundations.All. Require Import UniMath.MoreFoundations.All. Require Import UniMath.CategoryTheory.Core.Categories. Require Import UniMath.CategoryTheory.Core.Isos. Require Import UniMath.CategoryTheory.Core.TransportMorphisms. Require Import UniMath.CategoryTheory.Core.Functors. Require Import UniMath.CategoryTheory.Core.Univalence.