Book announcement : Modeling and Analysis of Communicating Systems

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Transition system specifications with negative premises

AbstractIn this article the general approach to Plotkin-style operational semantics of Groote and Vaandrager (1989) is extended to transition system specifications (TSSs) with rules that may contain negative premises. Two problems arise: firstly the rules may be inconsistent, and secondly it is not obvious how a TSS determines a transition relation. We present a general method, based on the stratification technique in logic programming, to prove consistency of a set of rules and we show how a specific transition relation can be associated with a TSS in a natural way. Then a special format for the rules, the ntyft/ntyxt format, is defined. It is shown that for this format three important theorems hold. The first theorem says that bisimulation is a congruence if all operators are defined using this format. The second theorem states that, under certain restrictions, a TSS in ntyft format can be added conservatively to a TSS in pure ntyft/ntyxt format. Finally, it is shown that the trace congruence for image-finite processes induced by the pure ntyft/ntyxt format is precisely bisimulation equivalence

A probablistic analysis of the Game of the Goose

We analyse the traditional board game the Game of the Goose. We are particularly interested in the probability of the different players to win. We show that we can determine these probabilities for up to six players. Our original motivation to investigate this game came from progress in stochastic process theories which prompted us to ask ourselves whether those methods are capable of dealing with well known probabilistic games. As these games have large state spaces, this is not trivial. As a side effect we found that common wisdom about this game is not true

Linearization in parallel pCRL

AbstractWe describe a linearization algorithm for parallel pCRL processes similar to the one implemented in the linearizer of the μCRL Toolset. This algorithm finds its roots in formal language theory: the `grammar' defining a process is transformed into a variant of Greibach Normal Form. Next, any such form is further reduced to linear form, i.e., to an equation that resembles a right-linear, data-parametric grammar. We aim at proving the correctness of this linearization algorithm. To this end we define an equivalence relation on recursive specifications in μCRL that is model independent and does not involve an explicit notion of solution

Verification of temporal properties of processes in a setting with data

We define a value-based modal mu-calculus, built from first-order formulas, modalities, and fixed point operators parameterized by data variables, which allows to express temporal properties involving data. We interpret this logic over muCRL terms defined by linear process equations. The satisfaction of a temporal formula by a muCRL term is translated to the satisfaction of a first-order formula containing parameterized fixed point operators. We provide proof rules for these fixed point operators and show their applicability on various examples