Definition local_out_of_reach mu (m : mem) (b : block) (ofs : Z): Prop :=
  locBlocksTgt mu b = true /\
  forall b0 delta, local_of mu b0 = Some (b, delta) ->
                  (~ Mem.perm m b0 (ofs - delta) Max Nonempty \/
                   pubBlocksSrc mu b0 = false).

Lemma REACH_is_closed: forall R m1, REACH_closed m1 (fun b : block => REACH m1 R b).