proposition: Lemma row_perm1 A : row_perm 1 A = A.
proof: Proof. by apply/matrixP=> i j; rewrite mxE perm1. 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)