Normed Processes, Unique Decomposition, and Complexity of Bisimulation Equivalences

We propose a decision procedure for a general class of normed commutative process rewrite systems and their induced bisimulation equivalences. Our technique is inspired by the polynomial-time algorithm for strong bisimilarity on normed Basic Parallel Processes (BPP), developed by Hirshfeld, Jerrum and Moller. As part of our framework we present a generic unique decomposition result, which we obtain by building on a characterization by Luttik and van Oostrom. We apply our general technique to derive polynomial-time algorithms for strong bisimilarity on normed BPP with communication and for distributed bisimilarity on all BPP with communication. Moreover, our technique yields a PSPACE upper bound for weak and branching bisimilarity on totally normed BPP.