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Conjunctive Query Containment over Trees

  • Henrik Björklund
  • Wim Martens
  • Thomas Schwentick
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4797)

Abstract

The complexity of containment and satisfiability of conjunctive queries over finite, unranked, labeled trees is studied with respect to the axes Child, nextSibling, their transitive and reflexive closures, and Following. For the containment problem a trichotomy is presented, classifying the problems as in PTIME, coNP-complete, or Π 2 P -complete. For the satisfiability problem most problems are classified as either in PTIME or NP-complete.

Keywords

Free Variable Truth Assignment Conjunctive Query Query Graph XPath Query 
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.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • Henrik Björklund
    • 1
  • Wim Martens
    • 1
  • Thomas Schwentick
    • 1
  1. 1.University of Dortmund 

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