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Acta Informatica

, Volume 6, Issue 4, pp 407–415 | Cite as

On proving that certain languages are not ETOL

  • A. Ehrenfeucht
  • G. Rozenberg
Article

Summary

In this paper a partial characterization for a subclass of ETOL languages is obtained. The main result binds together the number of occurrences (in words of a given ETOL language) of letters, from a given set, with their distribution. It provides a very helpful tool to prove that certain languages are not ETOL.

Keywords

Information System Operating System Data Structure Communication Network Information Theory 
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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References

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    Ehrenfeucht, A., Rozenberg, G.: Nonterminals versus homomorphisms in defining languages for some classes of rewriting systems. Acta Informatica 4, 87–106 (1974)Google Scholar
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    Ginsburg, S.: The mathematical theory of context-free languages. New York: Me Graw-Hill 1966Google Scholar
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    Lindenmayer, A.: Mathematical models for cellular interactions in development. J. Theoretical Biology 18, 280–315 (1968)Google Scholar
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    Lindenmayer, A., Rozenberg, G.: Developmental systems and languages. Proc. 4th Annual ACM Symposium on Theory of Computing, Denver (Colo.) 1972Google Scholar
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    Rozenberg, G.: Direction controlled programmed grammars. Acta Informatica 1, 242–252 (1972)Google Scholar
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    Rozenberg, G.: Extension of tabled OL systems and languages. Internat. J. Computer and Information Sciences 2, 311–336 (1973)Google Scholar

Copyright information

© Springer-Verlag 1976

Authors and Affiliations

  • A. Ehrenfeucht
    • 1
  • G. Rozenberg
    • 2
  1. 1.Department of Computer ScienceUniversity of Colorado at BoulderBoulderUSA
  2. 2.Institute of MathematicsUtrecht UniversityUtrecht-UithofThe Netherlands

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