Mathematical systems theory

, Volume 5, Issue 2, pp 164–167 | Cite as

On ywo-way, two-tape automata

  • David Pager


Two-way, two-tape automata were first considered in Rabin and Scott [1]. We show how surprisingly powerful these machines are by describing some programming techniques that can be implemented on them, and by proving, by means of these techniques, that there exists a universal two-symbol, two-way, two-tape automaton. We then argue that in contradiction to an assertion by Rabin and Scott, the class of sets of pairs of tapes definable by two-way, two-tape automata is not closed under most Boolean operations.


Computational Mathematic Boolean Operation Programming Technique 
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  1. [1]
    M. O. Rabin andD. Scott, Finite automata and their decision problems,IBM J. Res. Develop. 3 (1959), 114–125. Also in:Sequential Machines (ed. E. F. Moore), Addison-Wesley, Reading, Mass., 1964.Google Scholar
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    J. McCarthy, Review of [1],Math. Reviews 21, 1960, # 2559.Google Scholar
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    T. H. Crowley, Review of [1],IRE Trans. Electronic Computers 8 (1959), 407.Google Scholar
  4. [4]
    C. C. Elgot, Review of [1],J. Symbolic Logic 25 (1960), 163–164.Google Scholar

Copyright information

© Springer-Verlag New York Inc. 1971

Authors and Affiliations

  • David Pager
    • 1
  1. 1.University of HawaiiHonoluluUSA

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