(* Algebraic integers. *)
Definition Aint : pred_class :=
fun x : algC => minCpoly x \is a polyOver Cint.
Fact Aint_key : pred_key Aint. Proof. by []. Qed.
Canonical Aint_keyed := KeyedPred Aint_key.

Lemma root_monic_Aint p x :
root p x -> p \is monic -> p \is a polyOver Cint -> x \in Aint.