Planning as model checking: the performance of ProB vs NuSMV

In this paper we investigate the feasibility of using two different model-checking techniques for solving a number of classical AI planning problems. The ProB model checker, based on mathematical set theory and first-order logic, is specifically designed to validate specifications of concurrent programs written in the B specification language. ProB uses a constraint logic programming environment to perform model checking. NuSMV is the other model checker used in this work. It is an extension of SMV and makes use of symbolic model checking techniques to deal with the state explosion problem common to model checking in general. The problem is represented using Binary Decision Diagrams and model checking is performed using tableaux theorem proving techniques. The scope of the problems chosen is currently limited but it is envisaged that the methodology proposed could usefully be extended to larger planning problems.