intros x H'; unfold FSucc in |- *.
generalize (Z_eq_bool_correct (Fnum x) (pPred (vNum b)));
case (Z_eq_bool (Fnum x) (pPred (vNum b))); auto.
intros H'0; Contradict H'0; auto.
Qed.

Theorem FSuccSimpl2 :
forall x : float,
Fnum x = (- nNormMin radix precision)%Z ->
Fexp x <> (- dExp b)%Z ->
FSucc x = Float (- pPred (vNum b)) (Zpred (Fexp x)).