(*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 start_thread_det: forall tp m tid (cnt: containsThread tp tid) tp' m' tp'' m'' (Hstart: start_thread m cnt tp' m') (Hstart': start_thread m cnt tp'' m''), tp' = tp'' /\ m' = m''.