Canonical Crat_span_opprPred s := OpprPred (Crat_span_zmod_closed s).
Canonical Crat_span_addrPred s := AddrPred (Crat_span_zmod_closed s).
Canonical Crat_span_zmodPred s := ZmodPred (Crat_span_zmod_closed s).
Section MoreAlgCaut.
Implicit Type rR : unitRingType.

Lemma alg_num_field (Qz : fieldExtType rat) a : a%:A = ratr a :> Qz.