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

(** Concat is commutative with eq when ok. *)
Theorem eq_concat_comm : forall A (E F : gen_env A),
ok (E & F) ->
(E & F) ≍ (F & E).