Abstract
The Petri-net-based formalism of mobile object-net systems (Mons) is used to model concurrent systems with dynamically changing environments, such as mobile objects. The tokens in Mons are themselves Petri nets, which gives the formalism an additional (vertical) dimension of nesting. Traditional Petri nets have essentially a horizontal structure, given by the fact that markings are multisets. The question arises, whether Mons can be regarded as a canonical extension of such Petri nets. Due to the nested nature of Mons, the answer is not obvious. We first give the formal definition of Mons and then prove some properties of the formalism, showing that, with respect to interleaving semantics (i.e. firing sequences), Mons can indeed be viewed as a canonical extension of traditional Petri nets. We then define Mons processes, also as a canonical extension of standard Petri net processes.