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The research examines liveness and progress properties of concurrent systems and their on-the-fly verification. An alternative formalism to Büchi automata, called testing automata, is developed. The basic idea of testing automata is to observe changes in the values of state propositions instead of the values. Therefore, the testing automata are able to(More)
Many algorithms for computing minimal coverability sets for Petri nets prune futures. That is, if a new marking strictly covers an old one, then not just the old marking but also some subset of its successor markings is discarded from search. In this publication, a simpler algorithm that lacks future pruning is presented and proven correct. Its performance(More)
A formalism is presented that is intended to combine basic properties of both state-based and action-based verification. In state-based verification the behaviour of the system is described in terms of the properties of its states, whereas action-based methods concentrate on transitions between states. A typical state-based approach consists of representing(More)
—Fairness assumptions are needed to verify liveness properties of concurrent systems. In this paper we explore the so-called unconditional fairness in Markov decision processes (MDPs), which is a prerequisite for quantitative assume-guarantee reasoning. Unconditional fairness refers to executions where all processes are guaranteed to participate. We prove(More)
Tampere Verification Tool (TVT) is a collection of programs for automated verification of concurrent and reactive systems. TVT has its roots in process algebras and explicit state space exploration, but in addition to actions, our formalism allows use of state-based information in the form of truth-valued state propositions. Furthermore, it contains three(More)
Minimal counterexamples are desirable, but expensive to compute. We propose four algorithms for computing small counterexamples that approximate the shortest case. Three of these use a new algorithm for automata-theoretic linear-time model checking, based on an early algorithm by Dijk-stra for detecting strongly connected components. All four of the(More)
A major obstacle for using partial order reduction in the context of real time verification is that the presence of clocks and clock constraints breaks the usual diamond structure of otherwise independent transitions. This is especially true when information of the relative values of clocks is preserved in the form of diagonal constraints. However, when(More)