Comments on 'Maximally permissive supervisor synthesis based on a new   constraint transformation method'
  Luo et al. proposed a new method to design the maximally permissive and efficient supervisor for enforcing linear constraints on an ordinary Petri net with uncontrollable transitions. In order to develop this method, Theorem 3 is given. It is claimed that 'a linear constraint can be equivalently transformed at an uncontrollable transition into a disjunction of weakly admissible ones.' However, this result is erroneous. In this correspondence paper, a counterexample contradicting it is presented. 
Shouguang Wang, Jing Yang and Mengchu Zhou
cs.SY cs.FL