Instance Inhabitant_share : Inhabitant share := Share.bot.(* TODO: remove this, it's already in sublist.v *) 
Instance Inhabitant_mpred : Inhabitant mpred := @FF mpred Nveric.

Lemma approx_imp : forall n P Q, compcert_rmaps.RML.R.approx n (predicates_hered.imp P Q) = compcert_rmaps.RML.R.approx n (predicates_hered.imp (compcert_rmaps.RML.R.approx n P) (compcert_rmaps.RML.R.approx n Q)).