proposition: Fact mulfxA : associative (subfext_mul).
proof: Proof. elim/quotW=> x; elim/quotW=> y; elim/quotW=> w; rewrite !piE /subfx_mul_rep. by rewrite !poly_rV_modp_K [_ %% p0 * _]mulrC !modp_mul // mulrA mulrC. 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)