intros p H' H'0.
case (Rle_or_lt firstNormalPos p); intros Lt0; auto with real.
case (FnormalLtPos p firstNormalPos); auto.
apply firstNormalPosNormal.
intros H'1; Contradict H'1; unfold firstNormalPos in |- *; simpl in |- *.
apply Zle_not_lt; auto with float.
intros H'1; elim H'1; intros H'2 H'3; Contradict H'3.
unfold firstNormalPos in |- *; simpl in |- *.
apply Zle_not_lt.
rewrite <- (Zabs_eq (Fnum p)); auto with float zarith.
apply pNormal_absolu_min; auto.
apply LeR0Fnum with (radix := radix); auto with arith.
Qed.

Theorem FnormalLtFirstNormalNeg :
forall p : float, Fnormal p -> (p <= 0)%R -> (p <= Fopp firstNormalPos)%R.