Module Import NBasePropMod1 := NBaseProp N1.(* This makes the tactic induct available. Since it is taken from
(NBasePropFunct NAxiomsMod1), it refers to induction on N1. *)

Module Hom12 := Homomorphism N1 N2.Module Hom21 := Homomorphism N2 N1.Local Notation h12 := Hom12.natural_isomorphism.Local Notation h21 := Hom21.natural_isomorphism.

Lemma inverse_nat_iso : forall n : N1.t, h21 (h12 n) == n.