intros.
destruct Q as [?Q ?Q ?Q ?Q].
eapply semax_post; eauto; intros; apply andp_left2; simpl; auto; normalize.
Qed.

Lemma derives_frame_PQR:
forall R1 R2 Delta P Q P' Q' R1',
ENTAIL Delta, PROPx P (LOCALx Q (SEPx R1)) |-- PROPx P' (LOCALx Q' (SEPx R1')) ->
ENTAIL Delta, PROPx P (LOCALx Q (SEPx (R1++R2))) |-- PROPx P' (LOCALx Q' (SEPx (R1'++R2))).