intros p q H' H'0; red in |- *; intros H'1.
case (Rtotal_order 0 p); intros H'2.
absurd (q < p)%R.
rewrite <- H'1; auto with real.
apply FsubnormalnormalLtPos; auto with real.
rewrite <- H'1; auto with real.
absurd (p < q)%R.
rewrite <- H'1; auto with real.
apply FsubnormalnormalLtNeg; auto with real.
rewrite <- H'1; auto with real.
elim H'2; intros H'3; try rewrite <- H'3; auto with real.
elim H'2; intros H'3; try rewrite <- H'3; auto with real.
Qed.

Theorem FcanonicUnique :
forall p q : float, Fcanonic p -> Fcanonic q -> p = q :>R -> p = q.