Displaying similar documents to “Comparing Complexity Functions of a Language and Its Extendable Part”

Consensual languages and matching finite-state computations

Stefano Crespi Reghizzi, Pierluigi San Pietro (2011)

RAIRO - Theoretical Informatics and Applications

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An ever present, common sense idea in language modelling research is that, for a word to be a valid phrase, it should comply with multiple constraints at once. A new language definition model is studied, based on agreement or consensus between similar strings. Considering a regular set of strings over a bipartite alphabet made by pairs of unmarked/marked symbols, a match relation is introduced, in order to specify when such strings agree. Then a regular set over the bipartite alphabet...

Consensual languages and matching finite-state computations

Stefano Crespi Reghizzi, Pierluigi San Pietro (2011)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Similarity:

An ever present, common sense idea in language modelling research is that, for a word to be a valid phrase, it should comply with multiple constraints at once. A new language definition model is studied, based on agreement or consensus between similar strings. Considering a regular set of strings over a bipartite alphabet made by pairs of unmarked/marked symbols, a match relation is introduced, in order to specify when such strings agree. Then a regular set over the bipartite alphabet...

Complexity results for prefix grammars

Markus Lohrey, Holger Petersen (2005)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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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.

On the expressive power of the shuffle operator matched with intersection by regular sets

Joanna Jȩdrzejowicz, Andrzej Szepietowski (2001)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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We investigate the complexity of languages described by some expressions containing shuffle operator and intersection. We show that deciding whether the shuffle of two words has a nonempty intersection with a regular set (or fulfills some regular pattern) is NL-complete. Furthermore we show that the class of languages of the form L ∩ R , with a shuffle language L and a regular language R , contains non-semilinear languages and does not form a family of mildly context- sensitive languages. ...