The complexity of nonrepetitive coloring

  • Authors:
  • Dániel Marx;Marcus Schaefer

  • Affiliations:
  • Department of Computer Science and Information Theory, Budapest University of Technology and Econonomics, Budapest H-1521, Hungary;Department of Computer Science, DePaul University, Chicago, IL 60604, United States

  • Venue:
  • Discrete Applied Mathematics
  • Year:
  • 2009

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Abstract

A coloring of a graph is nonrepetitive if the graph contains no path that has a color pattern of the form xx (where x is a sequence of colors). We show that determining whether a particular coloring of a graph is nonrepetitive is coNP-hard, even if the number of colors is limited to four. The problem becomes fixed-parameter tractable, if we only exclude colorings xx up to a fixed length k of x.