intros x H H0; rewrite CanonicFulp; auto.
apply FSuccDiffPos; auto.
Qed.

(* Specifications: *)
Theorem FNSuccUlpPos :
forall x : float,
Fcanonic radix b x ->
(0 <= x)%R -> Fminus radix (FNSucc b radix precision x) x = Fulp x :>R.