intros x H H0.
unfold FNSucc in |- *.
rewrite FcanonicFnormalizeEq; auto with arith.
apply FSuccUlpPos; auto.
Qed.

Theorem FulpFabs : forall f : float, Fulp f = Fulp (Fabs f) :>R.
intros f; unfold Fulp in |- *; case (Rle_or_lt 0 f); intros H'.