proposition: Lemma submxrowN m (B : 'M[V]_(m, sq)) j : submxrow (- B) j = - submxrow B j.
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)