proposition: Lemma tr_submxcol n (A : 'M[T]_(sp, n)) i : (submxcol A i)^T = (submxrow A^T i).
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)