Mathematical systems theory

, Volume 7, Issue 2, pp 185–192

An infinite hierarchy of intersections of context-free languages

Authors

  • Leonard Y. Liu
    • International Business Machines Corporation
  • Peter Weiner
    • Department of Computer ScienceYale University
Article

DOI: 10.1007/BF01762237

Cite this article as:
Liu, L.Y. & Weiner, P. Math. Systems Theory (1973) 7: 185. doi:10.1007/BF01762237

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.

Copyright information

© Springer-Verlag New York Inc. 1973