Defining contexts in context-free grammars

Mikhail Barash, Alexander Okhotin

Research outputpeer-review

5 Citations (Scopus)


Conjunctive grammars (Okhotin, 2001) are an extension of the standard context-free grammars with a conjunction operation, which maintains most of their practical properties, including many parsing algorithms. This paper introduces a further extension to the model, which is equipped with quantifiers for referring to the left context, in which the substring being defined does occur. For example, a rule A → a & ◁B defines a string a, as long as it is preceded by any string defined by B. The paper gives two equivalent definitions of the model-by logical deduction and by language equations-and establishes its basic properties, including a transformation to a normal form, a cubic-time parsing algorithm, and another recognition algorithm working in linear space.

Original languageEnglish
Title of host publicationLanguage and Automata Theory and Applications - 6th International Conference, LATA 2012, Proceedings
Number of pages13
Publication statusPublished - 12 Mar 2012
Event6th International Conference on Language and Automata Theory and Applications, LATA 2012 - A Coruna
Duration: 5 Mar 20129 Mar 2012

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume7183 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference6th International Conference on Language and Automata Theory and Applications, LATA 2012
CityA Coruna

Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)

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