Definition CReal_of_DReal_scale (x : DReal) : Z :=
  Qbound_lt_ZExp2 (Qabs (CReal_of_DReal_seq x (-1)) + 2)%Q.

Lemma CReal_of_DReal_bound : forall (x : DReal), QBound (CReal_of_DReal_seq x) (CReal_of_DReal_scale x).