(** ** Lemmas about erased values*)

  Definition isDefined v :=
    match v with
    | Vundef => false
    | _ => true
    end.

Lemma val_erasure_intofsingle: forall v v', val_erasure v v' -> val_erasure (Val.maketotal (Val.intofsingle v)) (Val.maketotal (Val.intofsingle v')).