Non-deterministic two-tape automata are more powerful than deterministic ones

  • W. Brauer
  • K. -J. Lange
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 182)


Non-deterministic two-tape automata as defined by Elgot and Mezei are similar to non-deterministic finite state acceptors — instead of reading from one tape, they can read simultaneously from two tapes. They accept just the rational subsets of X* × Y*, and are closely related to linear context-free grammars. It is shown that, in contrast to the one-tape case, deterministic two-tape automata are less powerful than non-deterministic ones. The counterexample is closely related to a linear context-free language of unbounded degree of ambiguity.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1984

Authors and Affiliations

  • W. Brauer
    • 1
  • K. -J. Lange
    • 1
  1. 1.Fachbereich InformatikUniversität HamburgHamburg 13West Germany

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