
theorem
  for CPNT be Colored_Petri_net, t being transition of CPNT st CPNT is
  Colored-PT-net-like & t in dom (the firing-rule of CPNT) holds ex CS be non
empty Subset of the ColoredSet of CPNT, I be Subset of *'{t}, O be Subset of {t
  }*' st (the firing-rule of CPNT ).t is Function of thin_cylinders(CS,I),
  thin_cylinders(CS,O);
