THE SPNs we have addressed in the previous
finite state space. In this chapter we focus on a special class of stochastic
SPNs with unbounded state space, known as one-place unbounded SPNs or infinite-state (abbreviated as iSPNs). In particular, we focus on a class of SPNs of which the underlying
CTMC has a QBD structure, for which efficient solution methods exist (see Chapter 8). The properties an SPN has to fulfill to belong to this class can be verified at the SPN level, without having to construct the reachability graph....