proposition: Lemma mdegU k : mdeg U_(k)%M = 1%N.
proof: Proof. by rewrite mdegE mdomU big_seq_fset1 cmUU. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap