Practical partial order reduction for CSP

Abstract

FDR is an explicit-state refinement checker for the process algebra CSP and, as such, is vulnerable to the state-explosion problem. In this paper, we show how a form of partial-order reduction, an automatic state reduction mechanism, can be utilised to soundly reduce the number of states that must be visited. In particular, we develop a compositional method for partial-order reduction that takes advantage of FDR’s internal, compositional, process representation. Further, we develop novel methods of preserving the traces of a process which allow partial-order reduction to be applied to arbitrary FDR refinement checks. We also provide details on how to efficiently implement the algorithms required for partial-order reduction.