Reversal complexity of multicounter and multihead machines
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- 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
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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