proposition: Lemma format_bpow_x: (0 < F2R d)%R -> generic_format beta fexp (bpow (mag beta x)).
proof: Proof. Proof with auto with typeclass_instances. intros Y. apply generic_format_bpow. apply valid_exp. rewrite <- Fexp_d; trivial. apply Z.lt_le_trans with (mag beta (F2R d))%Z. rewrite Cd; apply mag_generic_gt... now apply Rgt_not_eq. apply Hd. apply mag_le; trivial. apply Hd. Qed.
imports: Coq(ZArith Reals Psatz) Core Operations