dc.contributor.author Henzinger, Thomas A. en_US dc.contributor.author Nicollin, Xavier en_US dc.contributor.author Sifakis, Joseph en_US dc.contributor.author Yovine, Sergio en_US dc.date.accessioned 2007-04-23T16:33:58Z dc.date.available 2007-04-23T16:33:58Z dc.date.issued 1994-01 en_US dc.identifier.citation http://techreports.library.cornell.edu:8081/Dienst/UI/1.0/Display/cul.cs/TR94-1404 en_US dc.identifier.uri https://hdl.handle.net/1813/6182 dc.description.abstract We describe finite-state programs over real-numbered time in a guarded-command language with real-valued clocks or, equivalently, as finite automata with real-valued clocks. Model checking answers the question which states of a real-time program satisfy a branching-time specification (given in an extension of CTL with clock variables). We develop an algorithm that computes this set of states symbolically as a fixpoint of a functional on state predicates, without constructing the state space. For this purpose, we introduce a $\mu$-calculus on computation trees over real-numbered time. Unfortunately, many standard program properties, such as response for all nonzero execution sequences (during which time diverges), cannot be characterized by fixpoints: we show that the expressiveness of the timed $\mu$-calculus is incomparable to the expressiveness of timed CTL. Fortunately, this result does not impair the symbolic verification of "implementable" real-time programs-those whose safety constraints are machine-closed with respect to diverging time and whose fairness constraints are restricted to finite upper bounds on clock values. All timed CTL properties of such programs are shown to be computable as finitely approximable fixpoints in a simple decidable theory. en_US dc.format.extent 4559213 bytes dc.format.extent 576410 bytes dc.format.mimetype application/pdf dc.format.mimetype application/postscript dc.language.iso en_US en_US dc.publisher Cornell University en_US dc.subject computer science en_US dc.subject technical report en_US dc.title Symbolic Model Checking for Real-Time Systems en_US dc.type technical report en_US
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