Section Properties.
Implicit Types x y : TVar.
Implicit Types xs ys : list TVar.
(* ---------------------------------------------------------------------- *)
(** **** Abstract properties of ok *)
(* ---------------------------------------------------------------------- *)
(** **** Properties of binds *)

(** Binds is functional. *)
Theorem binds_eq_inv : forall A x (v w : A) (E : gen_env A),
x ∹ v ⋲ E -> x ∹ w ⋲ E ->
v = w.