proposition: Lemma det_mx11 (M : 'M[R]_1) : \det M = M 0 0.
proof: Proof. by rewrite {1}[M]mx11_scalar 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)