proposition: Lemma nrootCC_1 : forall c : CC, c [#] [0] -> {z : CC | z[^]2 [=] c}.
proof: Proof. intros. pattern c in |- *. apply C_cc_ap_zero; try assumption; intros. apply nrootCC_1_ap_imag. assumption. apply nrootCC_1_ap_real. assumption. Qed.
imports: CoRN.complex.CComplex Coq.Arith.Wf_nat Coq.setoid_ring.ArithRing