Journal of Logic, Language and Information

, Volume 8, Issue 1, pp 1–16

Off-Line Parsability and the Well-Foundedness of Subsumption

  • Shuly Wintner
  • Nissim Francez

DOI: 10.1023/A:1008252619710

Cite this article as:
Wintner, S. & Francez, N. Journal of Logic, Language and Information (1999) 8: 1. doi:10.1023/A:1008252619710


Typed feature structures are used extensively for the specification of linguistic information in many formalisms. The subsumption relation orders TFSs by their information content. We prove that subsumption of acyclic TFSs is well founded, whereas in the presence of cycles general TFS subsumption is not well founded. We show an application of this result for parsing, where the well-foundedness of subsumption is used to guarantee termination for grammars that are off-line parsable. We define a new version of off-line parsability that is less strict than the existing one; thus termination is guaranteed for parsing with a larger set of grammars.

computational linguistics parsing feature structures unification 

Copyright information

© Kluwer Academic Publishers 1999

Authors and Affiliations

  • Shuly Wintner
    • 1
    • 2
  • Nissim Francez
    • 1
  1. 1.Department of Computer ScienceTechnionIsrael
  2. 2.Institute of TechnologyHaifaIsrael

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