intros w; destruct w; intros n0.
- destruct n0; norm.
- unfold Nwcons.
rewrite gen_phiNword_cons.
reflexivity.
Qed.

(* Specifications: *)
Lemma gen_phiNword_ok : forall w1 w2,
Nweq_bool w1 w2 = true -> gen_phiNword w1 == gen_phiNword w2.