Ordering constraints over feature trees

  • Martin Müller
  • Joachim Niehren
  • Andreas Podelski
Session 5a
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1330)


Feature trees have been used to accommodate records in constraint programming and record like structures in computational linguistics. Feature trees model records, and feature constraints yield extensible and modular record descriptions. We introduce the constraint system fFTof ordering constraints interpreted over feature trees. Under the view that feature trees represent symbolic information, the relation ≤ corresponds to the information ordering (“carries less information than”). We present a polynomial algorithm that decides the satisfi ability of conjunctions of positive and negative information ordering constraints over feature trees. Our results include algorithms for the satisfiability problem and the entailment problem of FT in time O(n3). We also show that FT has the independence property and are thus able to handle negative conjuncts via entailment. Furthermore, we reduce the satisfiability problem of Dörre's weaksubsumption constraints to the satisfiability problem of FT. This improves the complexity bound for solving weak subsumption constraints from O(n5) to O(n3).


feature constraints tree orderings weak subsumption satisfiability entailment complexity 


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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Martin Müller
    • 1
  • Joachim Niehren
    • 1
  • Andreas Podelski
    • 2
  1. 1.Universität des SaarlandesGermany
  2. 2.Max-Planck-Institut für InformatikSaarbrückenGermany

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