proposition: Lemma CC_conj_mult : forall c c' : CC, CC_conj (c[*]c') [=] CC_conj c[*]CC_conj c'.
proof: Proof. intros c c'. elim c. intros x y. elim c'. intros x' y'. simpl in |- *. unfold cc_eq in |- *. simpl in |- *. split; rational. Qed.
imports: CoRN.reals.NRootIR