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

Theorem binds_dec : forall A x (v : A) (E : gen_env A),
(forall w w' : A, { w = w' } + { ¬ w = w' }) ->
{ x ∹ v ⋲ E } + { ¬ x ∹ v ⋲ E }.