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

Theorem all_binds_all_remove : forall A ys (E F : gen_env A),
ys ⊄ E -> E ⊏ F ->
E ⊏ (F ∖ ys).