(* MachStep that doesn't change the schedule,
    Reduces the set of valid schedules... 
   *)
  Inductive has_unique_running tp:Prop :=
  | HasUniqueRun i (cnti : ThreadPool.containsThread tp i) q:
      ThreadPool.getThreadC cnti = Krun q ->
      has_unique_running tp.(* MachStep that doesn't change the schedule,
    Reduces the set of valid schedules... 
   *)
  Inductive has_unique_running tp:Prop :=
  | HasUniqueRun i (cnti : ThreadPool.containsThread tp i) q:
      ThreadPool.getThreadC cnti = Krun q ->
      has_unique_running tp.

Lemma csafe_ksafe_equiv: forall st_ m tr, (forall n U, valid (tr, st_, m) U -> csafe (U, tr, st_) m n) -> (forall n U, valid (tr, st_, m) U -> ksafe_kstep (U, tr, st_) m n).