proposition: Lemma tr_submxrow n (A : 'M[T]_(n, sp)) j : (submxrow A j)^T = (submxcol A^T j).
proof: Proof. by apply/matrixP => k l; 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)