Acta Informatica

, Volume 1, Issue 4, pp 336–344 | Cite as

On non-determinancy in simple computing devices

  • Juris Hartmanis


This paper studies one-tape Turing machines with k read-only heads which are restricted to the original input. The main result shows that if any set accepted by such a 3-head non-deterministic Turing machine can be accepted by a deterministic Turing machine with more read-only heads, then the deterministic and non-deterministic context-sensitive languages are identical. Several related results are derived and some tantalizing open problems are discussed.


Information System Operating System Data Structure Communication Network Information Theory 
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Copyright information

© Springer-Verlag 1972

Authors and Affiliations

  • Juris Hartmanis
    • 1
  1. 1.Gesellschaft für Mathematik und Datenverarbeitung mbH BonnSt. AugustinFederal Republic of Germany

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