proposition: Lemma submxrow0 m j : submxrow (0 : 'M[V]_(m, sq)) j = 0.
proof: Proof. by apply/matrixP=> i i'; rewrite !mxE. 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)