Definition mem_ok (tp: dryThreadPool) m := 
   Smallstep.globals_not_fresh (Clight.genv_genv ge) m /\
   mem_wd2 m /\
  (forall i (CT: containsThread tp i),
      ctl_ok (Mem.nextblock m) (getThreadC CT)).

Lemma mem_ok_step: forall st m st' m' (Hmem: mem_ok (threadpool_of st) m), MachStep(Sem := Clight_newSem ge) (ThreadPool:= OrdinalPool.OrdinalThreadPool) (machineSig:= HybridMachine.DryHybridMachine.DryHybridMachineSig) st m st' m' -> mem_ok (threadpool_of st') m'.