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Summary: Sampled Semantics of Timed Automata
Parosh Abdulla, Pavel Krcal, and Wang Yi
Department of Information Technology,
Uppsala University, Sweden
Email: {parosh,pavelk,yi}@it.uu.se
Abstract. Sampled semantics of timed automata is a nite approxima-
tion of their dense time behavior. While the former is closer to the actual
software or hardware systems with a xed granularity of time, the ab-
stract character of the latter makes it appealing for system modeling and
verication. We study one aspect of the relation between these two se-
mantics, namely checking whether the system exhibits some qualitative
(untimed) behaviors in the dense time which cannot be reproduced by
any implementation with a xed sampling rate. More formally, the sam-
pling problem is to decide whether there is a sampling rate such that all
qualitative behaviors (the untimed language) accepted by a given timed
automaton in dense time semantics can be also accepted in sampled se-
mantics. We show that this problem is decidable.
1 Introduction
Dense time semantics allows timed automata [AD94] to delay for arbitrary real
valued amounts of time. This includes also arbitrarily small delays and delays
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