intros p r H' H'0.
rewrite <- (Fopp_Fopp (FNPred b radix precision p)).
rewrite <- (Ropp_involutive r).
apply MaxOppMin.
rewrite FNPredFopFNSucc; auto.
rewrite Fopp_Fopp; auto.
(* Taking the pred of a max we get a min *)
apply MinMax; auto.
apply MaxOppMin; auto.
Contradict H'0.
rewrite <- (Ropp_involutive r); rewrite H'0; auto; unfold FtoRradix in |- *;
rewrite Fopp_correct; auto; apply Ropp_involutive.
Qed.

(* Specifications: *)
Theorem FmaxRep :
forall p q : float,
isMax p q -> exists m : Z, q = Float m (Fexp p) :>R.