Reactive systems are computing systems which are interactive, such as real-time systems, operating systems, concurrent systems, control systems, etc. They are among the most difficult computing systems to program....
A temporal language and system are presented which are based on branching time structure. By the introduction of symmetrically dual sets of temporal operators, it is possible to discuss properties which hold either along one path or along all paths. Consequently it is possible to express in this system all the properties that were previously expressible in… (More)
A common tool for proving the termination of programs is the <italic>well-founded set</italic>, a set ordered in such a way as to admit no infinite descending sequences. The basic approach is to find a <italic>termination function</italic> that maps the values of the program variables into some well-founded set, such that the value of the termination… (More)
Real-time systems operate in \real," continuous time and state changes may occur at any real-numbered time point. Yet many v eriication methods are based on the assumption that states are observed at integer time points only. What can we conclude if a real-time system has been shown \correct" for integral observations? Integer time veriication techniques… (More)
Motivated by applications to program verification, we study a decision procedure for satisfiability in an expressive fragment of a theory of arrays, which is parameterized by the theories of the array elements. The decision procedure reduces satisfiability of a formula of the fragment to satisfiability of an equisatisfiable quantifier-free formula in the… (More)
In this paper, Propositional Temporal Logic (PTL) is applied to the specification and synthesis of the synchronization part of communicating processes. To specify a process, a PTL formula that describes its sequence of communications is given. The synthesis is done by constructing a model of the given specifications using a tableau-like satisfiability… (More)
Hybrid systems are modeled as phase transition systems with sampling semantics. By identifying a set of important events it is ensured that all signiicant state changes are observed, thus correcting previous drawbacks of the sampling computations semantics. A proof rule for verifying properties of hybrid systems is presented and illustrated on several… (More)