proposition: Lemma msuppMn_le g n : msupp (g *+ n) `<=` msupp g.
proof: Proof. apply/fsubsetP=> k; rewrite -!mcoeff_neq0 mcoeffMn. by apply/contra_neq => ->; rewrite mul0rn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap