From quantity to quality

Thomas A. Henzinger, Orna Kupferman

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

16 Scopus citations


In temporal-logic model checking, we verify the correctness of a program with respect to a desired behavior by checking whether a structure that models the program satisfies a temporal-logic formula that specifies the behavior. The model-checking problem for the branching-time temporal logic CTL can be solved in linear running time, and model-checking tools for CTL are used successfully in industrial applications. The development of programs that must meet rigid real-time constraints has brought with it a need for real-time temporal logics that enable quantitative reference to time. Early research on real-time temporal logics uses the discrete domain of the integers to model time. Present research on real-time temporal logics focuses on continuous time and uses the dense domain of the reals to model time. There, model checking becomes significantly more complicated. For example, the model-checking problem for TCTL, a continuous-time extension of the logic CTL, is PSPACE-complete. In this paper we suggest a reduction from TCTL model checking to CTL model checking. The contribution of such a reduction is twofold. Theoretically, while it has long been known that model-checking methods for untimed temporal logics can be extended quite easily to handle discrete time, it was not clear whether find how untimed methods can handle the reset quantifier of TCTL, which resets a real-valued clock. Practically, our reduction enables anyone who has a tool for CTL model checking to use it for TCTL model checking. The TCTL model-checking algorithm that follows from our reduction is in PSPACE, matching the known bound for this problem. In addition, it enjoys the wide distribution of CTL model-checking tools and the extensive and fruitful research efforts and heuristics that have been put into these tools.

Original languageAmerican English
Title of host publicationHybrid and Real-Time Systems - International Workshop, HART 1997, Proceedings
EditorsOded Maler
PublisherSpringer Verlag
Number of pages15
ISBN (Print)354062600X, 9783540626008
StatePublished - 1997
Externally publishedYes
EventInternational Workshop on Hybrid And Real-Time Systems, HART 1997 - Grenoble, France
Duration: 26 Mar 199728 Mar 1997

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


ConferenceInternational Workshop on Hybrid And Real-Time Systems, HART 1997

Bibliographical note

Publisher Copyright:
© Springer-Verlag Berlin Heidelberg 1997.


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