proposition: Lemma det_scalar1 a : \det (a%:M : 'M[R]_1) = a.
proof: Proof. exact: det_scalar. 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)