Verifying Systems with Infinite but Regular State Spaces

Thanks to the development of a number of eeciency enhancing techniques, state-space exploration based veriication, and in particular model checking, has been quite successful for nite-state systems. This has prompted eeorts to apply a similar approach to systems with innnite state spaces. Doing so amounts to developing algorithms for computing a symbolic representation of the innnite state space, as opposed to requiring the user to characterize the state space by assertions. Of course, in most cases, this can only be done at the cost of forgoing any general guarantee of success. The goal of this paper is to survey a number of results in this area and to show that a surprisingly common characteristic of the systems that can be analyzed with this approach is that their state space can be represented as a regular language.