intros n m; elim m; simpl in |- *. auto with zarith.
intros n0 H H0; replace (S n0) with (1 + n0); auto with arith.
auto with zarith.
Qed.
Hint Resolve OddExp EvenExp: zarith.
Definition Feven (p : float) := Even (Fnum p).
Definition Fodd (p : float) := Odd (Fnum p).

Theorem FevenO : forall p : float, is_Fzero p -> Feven p.
intros p H'; red in |- *; rewrite H'; simpl in |- *; auto with zarith.