proposition: Lemma mdeg1 : mdeg 1%M = 0%N.
proof: Proof. by rewrite mdegE mdom1 big_seq_fset0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap