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| creator |
Diekert, Volker
| | Kufleitner, Manfred
| | date |
2009-06-16
| | | | description |
24 pages
| |
We give topological and algebraic characterizations as well as
language theoretic descriptions of the following subclasses of
first-order logic for omega-languages: Sigma2, FO2, the intersection
of FO2 and Sigma2, and Delta2 (and by duality Pi2 and the
intersection of FO2 and Pi2). These descriptions extend the
respective results for finite words. In particular, we relate the
above fragments to language classes of certain (unambiguous)
polynomials. An immediate consequence is the decidability of the
membership problem of these classes, but this was shown before by
Wilke and Bojanczyk and is therefore not our main focus. The paper
is about the interplay of algebraic, topological, and language
theoretic properties.
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application/pdf
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