intros p H; unfold Fdigit in |- *.
case (Z_eq_dec (Fnum p) 0); intros Z1.
rewrite Z1; simpl in |- *; auto with arith.
apply lt_S_n; apply le_lt_n_Sm.
rewrite <- digitPredVNumiSPrecision.
replace (S (digit radix (Fnum p))) with (digit radix (Fnum p) + 1).
rewrite <- digitAdd; auto with zarith.
apply digit_monotone; auto with float.
rewrite (fun x => Zabs_eq (Zpred x)); auto with float zarith.
rewrite Zmult_comm; rewrite Zpower_nat_1; auto with float zarith.
rewrite plus_comm; simpl in |- *; auto.
Qed.
Hint Resolve FsubnormalDigit: float.

Theorem pSubnormal_absolu_min :
forall p : float, Fsubnormal p -> (Zabs (Fnum p) < nNormMin)%Z.