Abstract
It is known that 1-tape-1-counter alternating Turing machines (ATMs) making a constant number of reversals recognize all recursively enumerable languages. Yamamoto and Noguchi raised the question whether 1-tape off-line ATMs with a constant reversal bound have the same computational power. Recently, Jiang has given a negative answer to this question by defining a recursive functionh(s,r,n) such that, for everys-state 1-tape off-line ATMM running inr reversals, the language accepted byM is inASPACE(h(s, r, n)). In this paper we continue the investigation of the reversal complexity of 1-tape off-line ATMs. We improve the result of Jiang showing that the functionh can be reduced to a functionf(s, r, n)≈ log log log logh(s,r,n). We also prove that 1-tape off-line ATMs recognize only recursive languages even if an arbitrary recursive bound (instead of only a constant) on the number of reversals is set. We conclude the paper by giving an astonishing reversal hierarchy theorem for the machines considered.
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References
B. S. Baker and R. V. Book, Reversal bounded multipushdown machines,J. Comput. System Sci.,8 (1974), 315–322.
A. K. Chandra, D. Kozen, and L. J. Stockmeyer, Alternation,J. Assoc. Comput. Mach.,28 (1981), 114–133.
J. E. Hopcroft and J. D. Ullman,Introduction to Automata Theory, Languages, and Computation, Addison-Wesley, Reading, MA, 1979.
O. H. Ibarra and T. Jiang, The power of alternating one-reversal counters and stacks.SIAM J. Comput.,20 (1991), 278–290.
T. Jiang, On the complexity of 1-tape ATMs and off-line 1-tape ATMs running in constant reversals,Theoret, Comput. Sci.,76 (1990), 323–330.
M. Kutytowski, M. Liskiewicz, and K. Loryś, Reversal complexity classes for alternating Turing machines,SIAM J. Comput.,19 (1990), 207–221.
R. E. Ladner, R. J. Lipton, and L. J. Stockmeyer, Alternating pushdown and stack automata,SIAM J. Comput,13 (1984), 135–155.
M. Liśkiewicz, K. Lorys, and M. Piotrów, On reversal-bounded alternating Turing machines,Theoret. Comput. Sci.,54 (1987), 331–339.
H. Yamamoto and S. Noguchi, Comparison of the power between reversal-bounded ATMs and reversal-bounded NTMs,Inform, and Comput.,75 (1987), 144–161.
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This research was supported by the Alexander-von-Humboldt-Stiftung while the author was visiting the Institut für Theoretische Informatik, TH Darmstadt, 6100 Darmstadt, Germany.
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Liśkiewicz, M. On the power of 1-tape off-line ATMs running in a bounded number of reversals. Math. Systems Theory 28, 329–339 (1995). https://doi.org/10.1007/BF01185400
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DOI: https://doi.org/10.1007/BF01185400