Section C.
Parameter g : forall m : nat, m <> 0 -> Prop.
Parameter f : forall (m : nat) (H : m <> 0), g m H.
Variable n : nat.
Variable ap_n : n <> 0.
Let delta := f n ap_n.
omega.
Qed.
End C.
intros;  omega.
Qed.

(* Bug that what caused by the use of intro_using in Omega *)
Lemma lem9 :
forall p q : nat, ~ (p <= q /\ p < q \/ q <= p /\ p < q) -> p < p \/ p <= p.