(* Higher Order *)

Definition assn_sub X a P : Assertion :=
  fun (st : state) =>
    P (t_update st X (aeval st a)).Notation "P [ X |-> a ]" := (assn_sub X a P) (at level 10).

Lemma silly1 : forall (P : nat -> nat -> Prop) (Q : nat -> Prop), (forall x y : nat, P x y) -> (forall x y : nat, P x y -> Q x) -> Q 42.