Hint Resolve normal_ret_assert_derives.

(* Specifications: *)
Lemma normal_ret_assert_FF:
forall ek vl rho, proj_ret_assert (normal_ret_assert (fun rho => FF)) ek vl rho = FF.
Lemma frame_normal:
forall P F,
frame_ret_assert (normal_ret_assert P) F = normal_ret_assert (fun rho => P rho * F rho).
Lemma proj_frame:
forall P F ek vl,
proj_ret_assert (frame_ret_assert P F) ek vl = fun rho => F rho * proj_ret_assert P ek vl rho.
Lemma proj_conj:
forall P F ek vl,
proj_ret_assert (conj_ret_assert P F) ek vl = fun rho => F rho && proj_ret_assert P ek vl rho.