proposition: Lemma mdegEw m (d : {fset I}) : finsupp m `<=` d -> mdeg m = (\sum_(i <- d) (m i))%N.
proof: Proof. move=> le; rewrite mdegE (big_fset_incl _ le) //. by move=> i i_in_d; rewrite -cmE_neq0 negbK => /eqP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap