Canonical Cint_span_addrPred s := AddrPred (Cint_span_zmod_closed s).
Canonical Cint_span_zmodPred s := ZmodPred (Cint_span_zmod_closed s).

(* Specifications: *)
(* Automorphism extensions. *)
Lemma extend_algC_subfield_aut (Qs : fieldExtType rat)
(QsC : {rmorphism Qs -> algC}) (phi : {rmorphism Qs -> Qs}) :
{nu : {rmorphism algC -> algC} | {morph QsC : x / phi x >-> nu x}}.
(* Extended automorphisms of Q_n. *)
Lemma Qn_aut_exists k n :
coprime k n ->
{u : {rmorphism algC -> algC} | forall z, z ^+ n = 1 -> u z = z ^+ k}.