rewrite d_eq; apply round_ge_generic...
apply generic_format_0.
now left.
Qed.

(* Specifications: *)
Lemma ln_beta_d:  (0< F2R d)%R ->
(ln_beta beta (F2R d) = ln_beta beta x :>Z).
Lemma ln_beta_d:  (0< F2R d)%R ->
(ln_beta beta (F2R d) = ln_beta beta x :>Z).