intros.
replace (Rabs x) with (FtoR radix (Fabs x)).
unfold FtoRradix in |- *.
apply maxMax with (b := b); auto with *.
unfold FtoRradix in |- *.
apply Fabs_correct; auto with *.
Qed.
(* What depends of the precision *)
Variable precision : nat.
Hypothesis precisionNotZero : precision <> 0.
Hypothesis pGivesBound : Zpos (vNum b) = Zpower_nat radix precision.

(* Specifications: *)
Theorem FboundNext :
forall p : float,
Fbounded b p ->
exists q : float, Fbounded b q /\ q = Float (Zsucc (Fnum p)) (Fexp p) :>R.