On the ω-language Expressive Power of Extended Petri Nets

In this paper, we study the expressive power of several monotonic extensions of Petri nets. We compare the expressive power of Petri nets, Petri nets extended with non-blocking arcs and Petri nets extended with transfer arcs, in terms of ω-languages. We show that the hierarchy of expressive powers of those models is strict. To prove these results, we propose original techniques that rely on well-quasi orderings and monotonicity properties.