Definition poly_of of phant R := polynomial.Identity Coercion type_poly_of : poly_of >-> polynomial.Variables (F : fieldType) (R : ringType) (f : {rmorphism F -> R}).Notation coefp i := (coefp_head tt i).Canonical polynomial_countType R := CountType _ (poly_countMixin R).ure on poly *)
Variable R : idomainType.

Lemma polyCK : cancel polyC (coefp 0).