Overlap-Free Regular Languages

  • Yo-Sub Han
  • Derick Wood
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4112)


We define a language to be overlap-free if any two distinct strings in the language do not overlap with each other. We observe that overlap-free languages are a proper subfamily of infix-free languages and also a proper subfamily of comma-free languages. Based on these observations, we design a polynomial-time algorithm that determines overlap-freeness of a regular language. We consider two cases: A language is specified by a nondeterministic finite-state automaton and a language is described by a regular expression. Furthermore, we examine the prime overlap-free decomposition of overlap-free regular languages and show that the prime overlap-free decomposition is not unique.


Regular Expression Regular Language Prime Decomposition Bridge State Pair Graph 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Yo-Sub Han
    • 1
  • Derick Wood
    • 2
  1. 1.System Technology DivisionKorea Institute of Science and TechnologyCheongryang, SeoulKorea
  2. 2.Department of Computer ScienceThe Hong Kong University of Science, and TechnologyKowloon, Hong Kong SAR

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