proposition: Lemma subfx_eval_is_additive : additive subfx_eval.
proof: Proof. by move=> x y; apply/eqP; rewrite piE -linearB modpD modNp. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq div) mathcomp(choice fintype tuple finfun bigop ssralg countalg) mathcomp(finalg zmodp matrix vector falgebra poly polydiv) mathcomp(mxpoly generic_quotient)