proposition: Lemma submxcolD m (B B' : 'M[V]_(sp, m)) i : submxcol (B + B') 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)