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Long unavoidable patterns

  • Ursula Schmidt
Contributed Papers
Part of the Lecture Notes in Computer Science book series (LNCS, volume 210)

Abstract

We examine long unavoidable patterns, unavoidable in the sense of Bean. Ehrenfeucht. McNulty. We prove that there is only one unavoidable pattern of length 2n−1 on an alphabet with n letters ; this pattern is a "quasi-power" in the sense of Schützenberger. We characterize the unavoidable words of length 2n−2 and 2n−3. Finally we show that every unavoidable word sufficiently long has a certain "quasi-power" as a subword.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1985

Authors and Affiliations

  • Ursula Schmidt
    • 1
  1. 1.LiTP, Université Paris VI Couloir 45-55PARIS Cedex 05

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