intros p H'; case (FevenSucProp p); auto.
Qed.

(* Specifications: *)
Theorem FevenSuc :
forall p : float, Feven p -> Fodd (FSucc b radix precision p).
Theorem FevenFop : forall p : float, Feven p -> Feven (Fopp p).
intros p; unfold Feven, Fopp in |- *; simpl in |- *; auto with zarith.