proposition: Lemma lcosetKV : rev_left_loop invg (fun x A => x *: A).
proof: Proof. by move=> x A; rewrite -lcosetM mulgV mul1g. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype div path tuple bigop prime finset)