proposition: Lemma submxElt : (A <= B)%MS = (A == B)%MS || (A < B)%MS.
proof: Proof. by rewrite -andb_orr orbN andbT. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype finfun bigop finset fingroup perm order) mathcomp(div prime binomial ssralg finalg zmodp matrix)