Power of cooperation and multihead finite systems

  • Pavol ďuriš
  • Tomasz Jurdziński
  • Miroslaw Kutyłowski
  • Krzysztof LoryŚ
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1443)


We consider systems of finite automata performing together computation on an input string. Each automaton has its own read head that moves independently of the other heads, but the automata cooperate in making state transitions. Computational power of such devices depends on the number of states of automata, the number of automata, and the way they cooperate. We concentrate our attention on the last issue. The first situation that we consider is that each automaton has a full knowledge on the states of all automata (multihead automata). The other extreme is that each automaton (called also a processor) has no knowledge of the states of other automata; merely, there is a central processing unit that may “freeze” any automaton or let it proceed its work (so called multiprocessor automata). The second model seems to be severely restricted, but we show that multihead and multiprocessor automata have similar computational power. Nevertheless, we show a separation result.


Central Processing Unit Finite Automaton Kolmogorov Complexity Input Symbol Input Word 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    A.O. Buda, Multiprocessor automata, IPL 25 (1987), 257–161.zbMATHMathSciNetCrossRefGoogle Scholar
  2. 2.
    P. ďuriš, Z. Galil, Sensing versus nonsensing automata, in Proc. ICALP'95, LNCS 944, Springer-Verlag 1995, pp. 455–463.Google Scholar
  3. 3.
    M. Holzer, Multi-head finite automata: data-independent versus data-dependent computations, in Proc. MFCS'97, LNCS 1295, Springer-Verlag 1995, pp. 299–308.Google Scholar
  4. 4.
    T. Jiang, M. Li, k one-way heads cannot do string-matching, in Proc. STOC '93, pp. 62–70.Google Scholar
  5. 5.
    M. Li, P. Vitanyi, An Introduction to Kolmogorov Complexity and its Applications, Springer-Verlag 1993.Google Scholar
  6. 6.
    B. Monien, Two-way multihead automata over a one-letter alphabet, R.A.I.R.O. Informatique théorique 14 (1980), 67–82.zbMATHMathSciNetGoogle Scholar
  7. 7.
    A.C. Yao, R.L. Rivest, k +1 heads are better than k, JACM 25 (1978), 337–340.zbMATHMathSciNetCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Pavol ďuriš
    • 1
  • Tomasz Jurdziński
    • 2
  • Miroslaw Kutyłowski
    • 2
  • Krzysztof LoryŚ
    • 2
  1. 1.Institute of InformaticsComenius UniversityBratislava
  2. 2.Computer Science InstituteUniversity of WrocławPoland

Personalised recommendations