Section BaseSetMulProp.
(* Properties of the purely multiplicative structure. *)
Variable gT : baseFinGroupType.
Implicit Types A B C D : {set gT}.
Implicit Type x y z : gT.
(* Set product. We already have all the pregroup identities, so we *)
(* only need to add the monotonicity rules.                        *)

Lemma sub_lcoset x A B : (A \subset x *: B) = (x^-1 *: A \subset B).