(*TODO: Move to ev_semantics*)
    Definition in_free_list (b : block) ofs xs :=
      exists x, List.In x xs /\
           let '(b', lo, hi) := x in
           b = b' /\
           (lo <= ofs < hi)%Z.

Lemma bare_execution_det: forall st m st' m' st'' m'' (Hstep: fine_execution st m st' m') (Hstep': fine_execution st m st'' m''), st' = st'' /\ m' = m''.