intros p q H' H'0 H'1 H'2; case H'; case H'0.
intros H'3 H'4; apply FnormalLtPos; auto.
intros H'3 H'4; absurd (p < q)%R; auto.
apply Rlt_asym.
apply FsubnormalnormalLtPos; auto.
apply Rle_trans with (r2 := FtoRradix p); auto with real.
intros H'3 H'4; case (Z_eq_dec (Fexp q) (- dExp b)); intros H'5.
right; split.
rewrite H'5; case H'4; intros H1 H2; case H2; auto.
apply Rlt_Fexp_eq_Zlt with (radix := radix); auto with zarith.
rewrite H'5; case H'4; intros H1 H2; case H2; auto.
left.
replace (Fexp p) with (- dExp b)%Z;
[ idtac | apply sym_equal; auto with float ].
case (Zle_lt_or_eq (- dExp b) (Fexp q)); auto with float zarith.
intros H'3 H'4; right; split.
apply trans_equal with (- dExp b)%Z; auto with float.
apply sym_equal; auto with float.
apply FsubnormalLt; auto.
Qed.

Theorem FcanonicLePos :
forall p q : float,
Fcanonic p ->
Fcanonic q ->
(0 <= p)%R ->
(p <= q)%R -> (Fexp p < Fexp q)%Z \/ Fexp p = Fexp q /\ (Fnum p <= Fnum q)%Z.