Logics for context-free languages

  • Clemens Lautemann
  • Thomas Schwentick
  • Denis Thérien
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 933)


We define matchings, and show that they capture the essence of context-freeness. More precisely, we show that the class of context-free languages coincides with the class of those sets of strings which can be defined by sentences of the form ∃ , where ϕ is first order, b is a binary predicate symbol, and the range of the second order quantifier is restricted to the class of matchings. Several variations and extensions are discussed.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1995

Authors and Affiliations

  • Clemens Lautemann
    • 1
  • Thomas Schwentick
    • 1
  • Denis Thérien
    • 2
  1. 1.Johannes Gutenberg-Universität MainzDeutschland
  2. 2.McGill University MontrealCanada

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