(** This inequality is tight since it is equal for n=1 and n=2 *)

(* Specifications: *)
Lemma Qpower_2powneg_le_inv: forall (n : positive),
(2 * 2 ^ Z.neg n <= 1 # n)%Q.
Lemma Pospow_lin_le_2pow: forall (n : positive),
(2 * n <= 2 ^ n)%positive.
Lemma CReal_cv_self : forall (x : CReal) (n : positive),
CReal_abs (x - inject_Q (seq x (Z.neg n))) <= inject_Q (1#n).
Lemma CReal_cv_self' : forall (x : CReal) (n : Z),
CReal_abs (x - inject_Q (seq x n)) <= inject_Q (2^n).