proposition: Lemma msuppN g : msupp (-g) = msupp g.
proof: Proof. by apply/fsetP=> k; rewrite -!mcoeff_neq0 mcoeffN oppr_eq0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap