(** Properties of [List.incl] (list inclusion). *)

(* Specifications: *)
Lemma incl_cons_inv:
forall (A: Type) (a: A) (b c: list A),
incl (a :: b) c -> incl b c.
Lemma incl_cons_inv:
forall (A: Type) (a: A) (b c: list A),
incl (a :: b) c -> incl b c.