Partial unfolding for compositional nonblocking verification of extended finite-state machines

Abstract

This working paper describes a framework for compositional nonblocking verification of reactive systems modelled as extended finite-state machines. The nonblocking property can capture the absence of livelocks and deadlocks in concurrent systems. Compositional verification is shown in previous work to be effective to verify this property for large discrete event systems. Here, these results are applied to extended finite-state machines communicating via shared memory. The model to be verified is composed gradually, simplifying components through abstraction at each step, while conflict equivalence guarantees that the final verification result is the same as it would have been for the non-abstracted model. The working paper concludes with an example showing the potential of compositional verification to achieve substantial state-space reduction.