Acta Informatica

, Volume 31, Issue 2, pp 161–206 | Cite as

Context-free text grammars

  • A. Ehrenfeucht
  • P. ten Pas
  • G. Rozenberg
Article

Abstract

A text is a tripleτ=(λ,ρ1,ρ2) such that λ is a labeling function, andρ1 andρ2 are linear orders on the domain of λ; hence τ may be seen as a word (λ,ρ1) together with an additional linear orderρ2 on the domain of λ. The orderρ2 is used to give to the word (λ,ρ1) itsindividual hierarchical representation (syntactic structure) which may be a tree but it may be also more general than a tree. In this paper we introducecontext-free grammars for texts and investigate their basic properties. Since each text has its own individual structure, the role of such a grammar should be that of a definition of a pattern common to all individual texts. This leads to the notion of ashapely context-free text grammar also investigated in this paper.

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Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • A. Ehrenfeucht
    • 1
  • P. ten Pas
    • 2
  • G. Rozenberg
    • 1
    • 2
  1. 1.Department of Computer ScienceUniversity of Colorado at BoulderBoulderUSA
  2. 2.Department of Computer ScienceLeiden UniversityLeidenThe Netherlands

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