Coarse abstractions make Zeno behaviours difficult to detect
An infinite run of a timed automaton is Zeno if it spans only a finite amount of time. Such runs are considered unfeasible and hence it is important to detect them, or dually, find runs that are non-Zeno. Over the years important improvements have been obtained in checking reachability properties fo...
Main Authors: | , |
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Format: | Article |
Language: | English |
Published: |
Logical Methods in Computer Science e.V.
2013-02-01
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Series: | Logical Methods in Computer Science |
Subjects: | |
Online Access: | https://lmcs.episciences.org/882/pdf |
Summary: | An infinite run of a timed automaton is Zeno if it spans only a finite amount
of time. Such runs are considered unfeasible and hence it is important to
detect them, or dually, find runs that are non-Zeno. Over the years important
improvements have been obtained in checking reachability properties for timed
automata. We show that some of these very efficient optimizations make testing
for Zeno runs costly. In particular we show NP-completeness for the
LU-extrapolation of Behrmann et al. We analyze the source of this complexity in
detail and give general conditions on extrapolation operators that guarantee a
(low) polynomial complexity of Zenoness checking. We propose a slight weakening
of the LU-extrapolation that satisfies these conditions. |
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ISSN: | 1860-5974 |