proposition: Lemma mcoeff_neq0 (g : {malg G[K]}) (k : K) : (g@_k != 0) = (k \in msupp g).
proof: Proof. by rewrite mcoeff_eq0 negbK. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap