Hidden Conditioned Homomorphism for XPath Fragment Containment

  • Yuguo Liao
  • Jianhua Feng
  • Yong Zhang
  • Lizhu Zhou
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3882)


As a query language for navigating XML trees and selecting a set of element nodes, XPath is ubiquitous in XML applications. One important issue of XPath queries is checking containment. In particular, we investigate a frequently used fragment of XPath that consists of node tests, the child axis (/), the descendant axis (//), branches ([]) and label wildcards (*). For special classes of pattern trees, the homomorphism algorithm returns false negatives. In order to address this problem, we propose two containment techniques, conditioned homomorphism and hidden conditioned homomorphism, and then present sound algorithms to check containment. The analytical result is given with an experiment.


Tree Pattern Conjunctive Query Tree Automaton XPath Query XPath Expression 
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 2006

Authors and Affiliations

  • Yuguo Liao
    • 1
  • Jianhua Feng
    • 1
  • Yong Zhang
    • 1
  • Lizhu Zhou
    • 1
  1. 1.Department of Computer Science and TechnologyTsinghua UniversityBeijingP.R. China

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