proposition: Lemma submxcolN m (B : 'M[V]_(sp, m)) i : submxcol (- B) i = - submxcol B i.
proof: Proof. by apply/matrixP => j j'; 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)