Section MoreAlgCaut.
Implicit Type rR : unitRingType.

Lemma restrict_aut_to_num_field (nu : {rmorphism algC -> algC}) :
(forall x, exists y, nu (QnC x) = QnC y) ->
{nu0 : {lrmorphism Qn -> Qn} | {morph QnC : x / nu0 x >-> nu x}}.