proposition: Lemma mxOver0 S : 0 \in S -> 0 \is a @mxOver m n _ S.
proof: Proof. exact: mxOver_const. 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 countalg finalg zmodp)