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Theoret. Informatics Appl. 39, 391-401 (2005)
DOI: 10.1051/ita:2005024
Complexity results for prefix grammars
Markus Lohrey and Holger PetersenUniversity of Stuttgart, FMI, Universitätsstr. 38, 70569 Stuttgart, Germany; lohrey@informatik.uni-stuttgart.de; petersen@informatik.uni-stuttgart.de
(Received February 5, 2004. Accepted July 5, 2004.)
Abstract
Resolving an open problem of Ravikumar and Quan, we show that
equivalence of prefix grammars is complete in PSPACE. We also show
that membership for these grammars is complete in P
(it was known that this problem is in P) and characterize the
complexity of equivalence and inclusion for monotonic grammars.
For grammars with several premises we show that membership
is complete in EXPTIME and hard for PSPACE for monotonic
grammars.
Mathematics Subject Classification. 03D03, 68Q17, 68Q42, 68Q45
Key words: Rewriting systems -- regular languages -- computational complexity
© EDP Sciences 2005
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