Four Small Universal Turing Machines

  • Turlough Neary
  • Damien Woods
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4664)

Abstract

We present small polynomial time universal Turing machines with state-symbol pairs of (5,5), (6,4), (9,3) and (18,2). These machines simulate our new variant of tag system, the bi-tag system and are the smallest known universal Turing machines with 5, 4, 3 and 2-symbols respectively. Our 5-symbol machine uses the same number of instructions (22) as the smallest known universal Turing machine by Rogozhin.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • Turlough Neary
    • 1
  • Damien Woods
    • 2
  1. 1.TASS, Department of Computer Science, National University of Ireland MaynoothIreland
  2. 2.Department of Computer Science, University College CorkIreland

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