Module Rmaps_Lemmas (R0: RMAPS).
Module R := R0.
Hint Resolve (@subp_sepcon _ Join_rmap Perm_rmap Sep_rmap): contractive.

Lemma ghost_same_level:
forall g phi, join_sub g (ghost_of phi) ->
ghost_fmap (approx (level phi)) (approx (level phi)) g = g.