intros P p r H' H'0 H'1.
cut (0 < Float 1%nat (- dExp b))%R;
[ intros Rl0
| unfold FtoRradix, FtoR in |- *; simpl in |- *; rewrite Rmult_1_l;
auto with real arith ].
cut (0 < r)%R; [ intros Rl1 | apply Rlt_le_trans with (1 := Rl0) ]; auto.
cut (0 <= r)%R; [ intros Rl2 | apply Rlt_le; auto ].
case H'.
intros H'2 H'3; Elimc H'3; intros H'3 H'4; Elimc H'4; intros H'4 H'5;
case (H'4 r p); auto; intros H'6.
apply Rle_trans with r; auto with real.
apply isMin_inv1 with (1 := H'6).
rewrite Rmult_comm; pattern r at 1 in |- *; replace r with (r * 1%nat)%R;
[ apply Rmult_le_compat_l | simpl; ring ]; auto with real arith.
case (MinEx b radix precision) with (r := r); auto with arith;
intros min Hmin.
cut (Fbounded b (Float (Fnum min) (Zsucc (Fexp min)))); [ intros F2 | idtac ].
cut (FtoRradix (Float (Fnum min) (Zsucc (Fexp min))) = (radix * min)%R :>R);
[ intros F2Eq | idtac ].
apply Rle_trans with (FtoRradix (Float (Fnum min) (Zsucc (Fexp min)))).
case H'6.
intros H'7 H'8; elim H'8; intros H'9 H'10; apply H'10; clear H'8; auto.
case (Rle_or_lt r (Float (Fnum min) (Zsucc (Fexp min)))); auto; intros Rlt0.
absurd (Float (Fnum min) (Zsucc (Fexp min)) <= min)%R.
apply Rgt_not_le.
rewrite F2Eq; auto with real.
rewrite Rmult_comm.
pattern (FtoRradix min) at 2 in |- *;
replace (FtoRradix min) with (min * 1%nat)%R; auto with real.
red in |- *; apply Rmult_lt_compat_l; auto with real arith.
case (RleMinR0 r min); auto.
intros H'8; case H'1.
intros H'11; absurd (Float 1%nat (- dExp b) <= min)%R.
apply Rgt_not_le; auto.
rewrite <- H'8; auto.
apply
(MonotoneMin b radix)
with (p := FtoRradix (Float 1%nat (- dExp b))) (q := r);
auto.
apply (RoundedModeProjectorIdem (isMin b radix)); auto.
apply MinRoundedModeP with (precision := precision); auto.
repeat split.
simpl in |- *; auto with zarith.
apply (vNumbMoreThanOne radix) with (precision := precision);
auto with zarith.
simpl in |- *; auto with zarith.
intros H'11; absurd (min = Float 1%nat (- dExp b) :>R).
rewrite <- H'8.
apply Rlt_dichotomy_converse; left; auto.
apply (MinUniqueP b radix r); auto.
rewrite <- H'11.
apply (RoundedModeProjectorIdem (isMin b radix)); auto.
apply MinRoundedModeP with (precision := precision); auto.
repeat split.
simpl in |- *; auto with zarith.
apply (vNumbMoreThanOne radix) with (precision := precision);
auto with zarith.
simpl in |- *; auto with zarith.
case Hmin.
intros H'8 H'11; elim H'11; intros H'12 H'13; apply H'13; clear H'11; auto.
apply Rlt_le; auto.
rewrite F2Eq.
apply Rmult_le_compat_l; auto with real arith.
replace 0%R with (INR 0); auto with real arith.
apply isMin_inv1 with (1 := Hmin).
unfold FtoRradix, FtoR in |- *; simpl in |- *.
rewrite powerRZ_Zs; auto with real zarith; ring.
cut (Fbounded b min);
[ unfold Fbounded in |- *; intros Fb0 | case Hmin; auto ].
elim Fb0; intros H H0; auto.
repeat (split; simpl in |- *); auto.
apply Zle_trans with (Fexp min); auto with zarith.
Qed.

Theorem roundedModeMoreMult :
forall (P : R -> float -> Prop) (p : float) (r : R),
RoundedModeP b radix P ->
P r p -> (r <= Float (- 1%nat) (- dExp b))%R -> (radix * r <= p)%R.