Abstract
In classical timed automata, as defined by Alur and Dill [AD90,AD94] and since widely studied, the only operation allowed to modify the clocks is the reset operation. For instance, a clock can neither be set to a non-null constant value, nor be set to the value of another clock nor, in a non-deterministic way, to some value lower or higher than a given constant. In this paper we study in details such updates.
We characterize in a thin way the frontier between decidability and undecidability. Our main contributions are the following :
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We exhibit many classes of updates for which emptiness is undecidable. These classes depend on the clock constraints that are used – diagonal-free or not – whereas it is well known that these two kinds of constraints are equivalent for classical timed automata.
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We propose a generalization of the region automaton proposed by Alur and Dill, allowing to handle larger classes of updates. The complexity of the decision procedure remains Pspace-complete.
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Bouyer, P., Dufourd, C., Fleury, E., Petit, A. (2000). Are Timed Automata Updatable?. In: Emerson, E.A., Sistla, A.P. (eds) Computer Aided Verification. CAV 2000. Lecture Notes in Computer Science, vol 1855. Springer, Berlin, Heidelberg. https://doi.org/10.1007/10722167_35
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DOI: https://doi.org/10.1007/10722167_35
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