Generalized innermost rewriting

We propose two generalizations of innermost rewriting for which we prove that termination of innermost rewriting is equivalent to termination of generalized innermost rewriting. As a consequence, by rewriting in an arbitrary TRS certain non-innermost steps may be allowed by which the termination behavior and efficiency is often much better, but never worse than by only doing innermost rewriting

State Space Reduction Using Partial τ-Confluence

We present an efficient algorithm to determine the maximal class of confluent t-transitions in a labelled transition system. Confluent t-transitions are inert with respect to branching bisimulation. This allows to use t-priorisation, which means that in a state with a confluent outgoing t-transition all other transitions can be removed, maintaining branching bisimulation. In combination with the removal of t-loops, and the compression of t-sequences this yields an efficient algorithm to reduce the size of large state spaces

Partial-order reduction for GPU model checking

\u3cp\u3eModel checking using GPUs has seen increased popularity over the last years. Because GPUs have a limited amount of memory, only small to medium-sized systems can be verified. For on-the-fly explicitstate model checking, we improve memory efficiency by applying partialorder reduction. We propose novel parallel algorithms for three practical approaches to partial-order reduction. Correctness of the algorithms is proved using a new, weaker version of the cycle proviso. Benchmarks show that our implementation achieves a reduction similar to or better than the state-of-the-art techniques for CPUs, while the amount of runtime overhead is acceptable.\u3c/p\u3

Automated verification of executable UML models

We present a fully automated approach to verifying safety properties of Executable UML models (xUML). Our tool chain consists of a model transformation program which translates xUML models to the process algebra mCRL2, followed by symbolic model checking using LTSmin. If a safety violation is found, an error trace is visualised as a UML sequence diagram. As a novel feature, our approach allows safety properties to be specified as UML state machines

Distributed analysis with μCRL:a compendium of case studies

\u3cp\u3eModels in process algebra with abstract data types can be analysed by state space generation and reduction tools. The μCRL toolset implements a suite of distributed verification tools for clusters of workstations. We illustrate their application to large case studies from a wide range of application areas, such as functional analysis, scheduling, security analysis, test case generation and game solving.\u3c/p\u3