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Two-way reading on words

  • M. Anselmo
Part III Communications
Part of the Lecture Notes in Computer Science book series (LNCS, volume 464)

Abstract

We study the phenomena produced when inversion of direction is allowed when reading a word. Two-way reading on a given language x can be reduced to left-to-right reading on a language containing x, which is regular whenever x is so. We present two characterizations of "zig-zag languages". We then consider and compare two possible ways of counting two-way reading on a regular language, and thus, of defining the behaviour of two-way automata. For each one definition, we show the construction of a one-way automaton equivalent in multiplicity to a given two-way automaton, this generalizing Rabin, Scott and Shepherdson's Theorem.

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References and Bibliography

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Copyright information

© Springer-Verlag Berlin Heidelberg 1990

Authors and Affiliations

  • M. Anselmo
    • 1
    • 2
  1. 1.L.I.T.P. - Université Paris 7Paris Cedex 05France
  2. 2.Dip. Mat. ed appl. - Univ. di PalermoPalermoItaly

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