-Generalizable All Variables.
-Require Import Preamble.
-Require Import General.
-Require Import ch1_3_Categories.
-Require Import ch1_4_Functors.
-Require Import ch1_5_Isomorphisms.
-
(*******************************************************************************)
(* Chapter 7.8: Equivalent Categories *)
(*******************************************************************************)
+Generalizable All Variables.
+Require Import Notations.
+Require Import Categories_ch1_3.
+Require Import Functors_ch1_4.
+Require Import Isomorphisms_ch1_5.
+Require Import NaturalIsomorphisms_ch7_5.
+
(* Definition 7.24 *)
Class EquivalentCategories `(C:Category)`(D:Category){Fobj}{Gobj}(F:Functor C D Fobj)(G:Functor D C Gobj) :=
{ ec_forward : F >>>> G ≃ functor_id C