proposition: Lemma mscalerI a p : (a *: p == 0) = (a == 0) || (p == 0).
proof: Proof. have [/eqP->| /(msuppZ p)/perm_size] := boolP (a == 0). by rewrite scale0r eqxx. by rewrite -!msupp_eq0; case: msupp => [|a1 l1]; case: msupp. 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