proposition: Fact subvs_mul1 : right_id subvs_one subvs_mul.
proof: Proof. by move=> x; apply/val_inj/algidr/(valP x). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype div tuple finfun bigop ssralg) mathcomp(finalg zmodp matrix vector poly)