In this paper, we propose a method for the automatic construction of an abstract state graph of an arbitrary system using the Pvs theorem prover. Given a parallel composition of sequential processes and a partition of the state space induced by predicates ~i, ..., ~ on the program variables which defines an abstract state space, we construct an abstract state graph, starting in the abstract initial state. The possible successors of a state are computed using the Pvs theorem prover by verifying for each index i if ~ or -~i is a postcondition of it. This allows an abstract state space exploration for arbitrary programs.

Abstract. We study property preserving transformations for reactive systems. The main idea is the use of simulationsparameterized by Galois connections( ), relating the lattices of properties of two systems. We propose and study a notion of preservation of properties expressed by formulas of a logic, by a function mapping sets of states of a system S into sets of states of a system S'. We g i v e results on the preservation of properties expressed in sublanguages of the branching time -calculus when two systems S and S' are related via h i-simulations. They can be used to verify a property for a system by v erifying the same property on a simpler system which i s a n abstraction of it. We s h o w also under which conditions abstraction of concurrent systems can be computed from the abstraction of their components. This allows a compositional application of the proposed veri cation method. This is a revised version of the papers 2] and 16] the results are fully developed in 27].

Weis (1) (2)*, Aline Cuénod (3) (4), Bastian Rieck (1) (2), Felipe Llinares-López (1) (2), Olivier Dubuis (8), Susanne Graf (7), Claudia Lang (8), Michael Oberle (9), Maximilian Brackmann (10), Kirstine K. Søgaard (3) (4), Michael Osthoff (5) (6), Karsten Borgwardt (1) (2)*+, Adrian Egli (3) (4)*+

No abstract

No abstract

Our data suggest that Propionibacterium associated prosthetic joint infections occur at a relative frequency that is comparable to many other pathogens. Clinical signs are generally subtle, but the spectrum includes also significant soft-tissue damages. In this study, a median of 9.5 biopsies per case, an incubation time of 14 days, and the aid of histopathological examinations proved to be helpful in establishing the diagnosis.

We present a method for the compositional construction of the minimal transition system that represents the semantics of a given distributed system. Our aim is to control the state explosion caused by the interleavings of actions of communicating parallel components by reduction steps that exploit global communication constraints given in terms of interface specifications. The effect of the method, which is developed for bisimulation semantics here, depends on the structure of the distributed system under consideration, and the accuracy of the interface specifications. However, its correctness is independent of the correctness of the interface specifications provided by the program designer.

No abstract