Definition spec_parametric (Q: address -> spec) : Prop :=
forall l l', exists pp, exists ok,
forall sh m,
Q l sh l' m =
(exists p, exists k, ok k /\ m @ l' =
YES sh p k (preds_fmap (approx (level m)) (approx (level m)) pp)).

Lemma YES_ext:
forall sh sh' rsh rsh' k p, sh=sh' -> YES sh rsh k p = YES sh' rsh' k p.