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