Lecture Notes in Computer Science Volume 1046, 1996, pp 255-268
Date: 07 Jun 2005

On the power of non-observable actions in timed automata

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Timed finite automata, introduced by Alur and Dill, are one of the most widely studied models for real-time systems. We focus in this paper on the power of silent transitions, i.e. ε-transitions, in such automata. We show that ε-transitions strictly increase the power of timed automata and that the class of timed languages recognized by automata with ε-transitions is much more robust than the corresponding class without ε-transitions. Our main result shows that these transitions increase the power of these automata only if they reset clocks.