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Mathematical systems theory

, Volume 7, Issue 2, pp 185–192 | Cite as

An infinite hierarchy of intersections of context-free languages

  • Leonard Y. Liu
  • Peter Weiner
Article

Abstract

The class of languages expressible as the intersection ofk context-free languages is shown to be properly contained within the class of languages expressible as the intersection ofk + 1 context-free languages. Hence an infinite hierarchy of classes of languages is exhibited between the class of context-sensitive languages and the class of context-free languages.

Keywords

Computational Mathematic Infinite Hierarchy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag New York Inc. 1973

Authors and Affiliations

  • Leonard Y. Liu
    • 1
  • Peter Weiner
    • 2
  1. 1.International Business Machines CorporationYorktown HeightsUSA
  2. 2.Department of Computer ScienceYale UniversityNew HavenUSA

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