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Summary: Algorithmic Improvements in Regular Model
Checking ?
Parosh Aziz Abdulla, Bengt Jonsson, Marcus Nilsson, and Julien d'Orso ??
Uppsala University, Dept. of Information Technology
P.O. Box 337, S-751 05 Uppsala, Sweden
fparosh,bengt,marcusn,juldorg@it.uu.se
Abstract. Regular model checking is a form of symbolic model check-
ing for parameterized and in nite-state systems, whose states can be
represented as nite strings of arbitrary length over a nite alphabet, in
which regular sets of words are used to represent sets of states. In earlier
papers, we have developed methods for computing the transitive closure
(or the set of reachable states) of the transition relation, represented by
a regular length-preserving transducer. In this paper, we present sev-
eral improvements of these techniques, which reduce the size of inter-
mediate approximations of the transitive closure: One improvement is
to pre-process the transducer by bi-determinization, another is to use a
more powerful equivalence relation for identifying histories (columns) of
states in the transitive closure. We also present a simpli ed theoretical
framework for showing soundness of the optimization, which is based on
commuting simulations. The techniques have been implemented, and we
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