(* *)
End nt_def.
(* Natural Transformations Setoid between F and G*)
Section setoid_nt.
Variables (C D : Category) (F G : Functor C D).
Definition Equal_NT (T T' : NT F G) := forall a : C, T a =_S T' a.

(* Specifications: *)
Lemma Equal_NT_equiv : Equivalence Equal_NT.
Canonical Structure NT_setoid : Setoid'' := Equal_NT_equiv.