Reversal complexity of multicounter and multihead machines

  • Juraj Hromkovič
Contributed Papers Complexity

DOI: 10.1007/BFb0039603

Part of the Lecture Notes in Computer Science book series (LNCS, volume 247)
Cite this paper as:
Hromkovič J. (1987) Reversal complexity of multicounter and multihead machines. In: Brandenburg F.J., Vidal-Naquet G., Wirsing M. (eds) STACS 87. STACS 1987. Lecture Notes in Computer Science, vol 247. Springer, Berlin, Heidelberg

Abstract

It is proved that the family of languages recognized by one-way real-time nondeterministic multicounter machines with constant number of counter reversals is not closed under complementation.

The best known lower bound Ω(n1/3/log2n) on the complexity measure REVERSALS·SPACE·PARALLELISM of multihead alternating machines is improved to Ω(n1/2/log2n). Several strongest lower bounds for different complexity measures are direct consequences of this result.

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Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Juraj Hromkovič
    • 1
  1. 1.Dept. of Theoretical Cybernetics and Mathematical InformaticsComenius UniversityBratislavaCzechoslovakia

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