Verifying Safety Properties of a Class of Infinite-State Distributed Algorithms

. We consider the problem of verifying correctness properties of a class of programs with states that are sets of ground atoms. Such programs can model specifications of telephone services, in which we are particularly interested. For this class of systems, we consider the problem of checking reachability properties. A large class of safety properties can also be reduced to the problem of checking reachability in a transformed system. The emphasis of our approach is on automated verification of such properties. Although the reachability problem is in general undecidable, we present a method for analyzing reachability properties, and show that it can be successfully applied to practical examples. The main idea of our method is the following. In order to check whether a certain set of "error" states can be reached from an initial state of the system, we first compute the set of "unsafe states" (i.e., states from which it is possible to reach an error state) as a fixpoint, and finally we ..