Section ClosedFieldQE.
Variables (F : fieldType) (F_closed : GRing.ClosedField.axiom F).
Notation fF := (@GRing.formula F).
Notation tF := (@GRing.term F).
Notation qf f := (GRing.qf_form f && GRing.rformula f).
Definition polyF := seq tF.
Definition isnull (p : polyF) : cps bool :=
'let n <- sizeT p; ret (n == 0%N).

Lemma isnullP (p : polyF) : isnull p ->_e (eval_poly e p == 0).