Displaying similar documents to “Some further remarks on the index of context-free languages”

Weightreducing grammars and ultralinear languages

Ulrike Brandt, Ghislain Delepine, Hermann K.-G. Walter (2004)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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We exhibit a new class of grammars with the help of weightfunctions. They are characterized by decreasing the weight during the derivation process. A decision algorithm for the emptiness problem is developed. This class contains non-contextfree grammars. The corresponding language class is identical to the class of ultralinear languages.