Generalized mutual exclusion contraints on nets with uncontrollable transitions

The authors study a class of specifications, called generalized mutual exclusion constraints, for discrete event systems modeled using place/transition nets. These specifications may be easily enforced by a set of places called monitors on a net system where all transitions are controllable. However, when some of the transitions of the net are uncontrollable, this technique is not always applicable. For some classes of nets, the authors prove that generalized mutual exclusion constraints may always be enforced by monitors, even in the presence of uncontrollable transitions