proposition: Lemma stablemxC x : stablemx V x%:M.
proof: Proof. by rewrite mul_mx_scalar scalemx_sub. 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 finalg zmodp matrix)