proposition: Lemma comp_mpolyEX p lq : p \mPo lq = \sum_(m <- msupp p) (p@_m *: ('X_[m] \mPo lq)).
proof: Proof. by apply/eq_bigr=> m _; rewrite mul_mpolyC comp_mpolyX. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype tuple finfun bigop finset binomial) mathcomp(order fingroup perm ssralg zmodp poly ssrint) mathcomp(matrix vector) mathcomp(bigenough) ssrcomplements freeg