proposition: Lemma trmx_conform m' n' m n (B : 'M_(m', n')) (A : 'M_(m, n)) : (conform_mx B A)^T = conform_mx B^T A^T.
proof: Proof. rewrite /conform_mx; do !case: eqP; rewrite ?mxE// => en em. by rewrite trmx_cast. 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)