Acta Informatica

, Volume 26, Issue 3, pp 279–284 | Cite as

The method of forced enumeration for nondeterministic automata

  • Róbert Szelepcsényi


Every family of languages, recognized by nondeterministic L(n) tape-bounded Turing machines, where L(n)≥logn, is closed under complement. As a special case, the family of context-sensitive languages is closed under complement. This solves the open problem from [4].


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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Hopcroft, J.E., Ullman, J.D.: Formal languages and their relation to automata. Reading: Addison-Wesley 1969Google Scholar
  2. 2.
    Immerman, N.: Nondeterministic space is closed under complementation. Proceedings of the 3rd Annual Conference Structure in Complexity Theory, 14–17 June 1988, Washington D.C. (also TH Report YALEU/DCS/TR 552, July 1987)Google Scholar
  3. 3.
    Immerman, N.: Descriptive and computational complexity, (unpublished manuscript, 1987)Google Scholar
  4. 4.
    Kuroda, S.Y.: Classes of languages and linear-bounded automata. Inf. Control 7, 207–233 (1964)Google Scholar
  5. 5.
    Szelepcsényi, R.: Context-sensitive languages are closed under complementation, TR Komensky University, April 1987 (in Slovak)Google Scholar
  6. 6.
    Szelepcsényi, R.: The method of Forcing for nondeterministic automata. Bull. Eur. Assoc. Theor. Comp. Sci. 33, 96–100 (1987)Google Scholar

Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • Róbert Szelepcsényi
    • 1
  1. 1.Department of Theoretical Cybernetics, Faculty of Mathematics and PhysicsKomensky UniversityBratislavaCzechoslovakia

Personalised recommendations