Displaying similar documents to “Rational stochastic automata in formal language theory”

Highly Undecidable Problems For Infinite Computations

Olivier Finkel (2009)

RAIRO - Theoretical Informatics and Applications

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We show that many classical decision problems about -counter -languages, context free -languages, or infinitary rational relations, are Π½ -complete, hence located at the second level of the analytical hierarchy, and “highly undecidable”. In particular, the universality problem, the inclusion problem, the equivalence problem, the determinizability problem, the complementability problem, and the unambiguity problem are all Π½ -complete for context-free -languages or for infinitary...

Polynomial languages with finite antidictionaries

Arseny M. Shur (2008)

RAIRO - Theoretical Informatics and Applications

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We tackle the problem of studying which kind of functions can occur as complexity functions of formal languages of a certain type. We prove that an important narrow subclass of rational languages contains languages of polynomial complexity of any integer degree over any non-trivial alphabet.

Unambiguous recognizable two-dimensional languages

Marcella Anselmo, Dora Giammarresi, Maria Madonia, Antonio Restivo (2006)

RAIRO - Theoretical Informatics and Applications

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We consider the family UREC of unambiguous recognizable two-dimensional languages. We prove that there are recognizable languages that are inherently ambiguous, that is UREC family is a proper subclass of REC family. The result is obtained by showing a necessary condition for unambiguous recognizable languages. Further UREC family coincides with the class of picture languages defined by unambiguous 2OTA and it strictly contains its deterministic counterpart. Some closure and non-closure...

CD-systems of stateless deterministic R(1)-automata governed by an external pushdown store

Benedek Nagy, Friedrich Otto (2011)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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We study cooperating distributed systems (CD-systems) of stateless deterministic restarting automata with window size 1 that are equipped with an external pushdown store. In this way we obtain an automata-theoretical characterization for the class of word languages that are linearizations of context-free trace languages.