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An infinite hierarchy of intersections of context-free languages

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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.

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Liu, L.Y., Weiner, P. An infinite hierarchy of intersections of context-free languages. Math. Systems Theory 7, 185–192 (1973). https://doi.org/10.1007/BF01762237

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  • Computational Mathematic
  • Infinite Hierarchy