Anaphora Resolution as Equality by Default

  • Ariel Cohen
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4410)


The resolution of anaphora is dependent on a number of factors discussed in the literature: syntactic parallelism, topicality, etc. A system that attempts to resolve anaphora will have to represent many of these factors, and deal with their interaction. In addition, there must be a principle that simply says that the system needs to look for an antecedent. Without such a principle, if none of the factors recommend a clear winner, the system will be left without an antecedent. This principle should work in such a way that, if there is exactly one good candidate antecedent, the system will choose it; if there are more than one, the system will still attempt to identify one, or, at least, draw some inferences about the likely antecedent; and, in case there is no candidate, the system will produce an accommodated or deictic reading.

Many systems embody some version of this principle procedurally, as part of the workings of their algorithm. However, because it is not explicitly formalized, it is hard to draw firm conclusions about what the system would do in any given case. In this paper I define a general principle of Equality by Default, formalize it in Default Logic, and demonstrate that it produces the desired behavior. Since all other factors can also be formalized in Default Logic, the principle does not need to be left implicit in the algorithm, and can be integrated seamlessly into the rest of the explicit rules affecting anaphora resolution.


Default Theory Default Logic Nonmonotonic Reasoning Discourse Referent Anaphora Resolution 
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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Asher, N.: Linguistic understanding and non-monotonic reasoning. In: Proceedings of the 1st International Workshop on Nonmonotonic Reasoning, New Paltz (1984)Google Scholar
  2. 2.
    Byron, D., Gegg-Harrison, W.: Evaluating optimality theory for pronoun resolution algorithm specification. In: Proceedings of the Discourse Anaphora and Reference Resolution Conference (DAARC2004), pp. 27–32 (2004)Google Scholar
  3. 3.
    Lascarides, A., Asher, N.: Temporal interpretation, discourse relations and common sense entailments. Linguistics and Philosophy 16, 437–493 (1993)CrossRefGoogle Scholar
  4. 4.
    Mitkov, R.: An uncertainty reasoning approach for anaphora resolution. In: Proceedings of the Natural Language Processing Pacific Rim Symposium (NLPRS’95), Seoul, Korea, pp. 149–154 (1995)Google Scholar
  5. 5.
    Poesio, M.: Semantic ambiguity and perceived ambiguity. In: van Deemter, K., Peters, S. (eds.) Semantic Ambiguity and Underspecification, pp. 159–201. CSLI, Stanford (1996)Google Scholar
  6. 6.
    Beaver, D.: The optimization of discourse anaphora. Linguistics and Philosophy 27(1), 3–56 (2004)CrossRefMathSciNetGoogle Scholar
  7. 7.
    Prince, A., Smolensky, P.: Optimality theory: Constraint interaction in generative grammar. Technical report, Rutgers University, New Brunswick, NJ and University of Colorado at Boulder (1993)Google Scholar
  8. 8.
    Reiter, R.: A logic for default reasoning. Artificial Intelligence 13, 81–132 (1980)zbMATHCrossRefMathSciNetGoogle Scholar
  9. 9.
    Williams, E.: Blocking and anaphora. Linguistic Inquiry 28, 577–628 (1997)Google Scholar
  10. 10.
    Hendriks, P., de Hoop, H.: Optimality theoretic semantics. Linguistics and Philosophy 24, 1–32 (2001)CrossRefGoogle Scholar
  11. 11.
    Bry, F., Yahya, A.: Positive unit hyperresolution tableaux and their application to minimal model generation. Journal of Automated Reasoning 25, 35–82 (2000)zbMATHCrossRefMathSciNetGoogle Scholar
  12. 12.
    van der Sandt, R.: Presupposition projection as anaphora resolution. Journal of Semantics 9, 333–377 (1992)CrossRefGoogle Scholar
  13. 13.
    Kamp, H., Reyle, U.: From Discourse to Logic. Kluwer Academic Publishers, Dordrecht (1993)Google Scholar
  14. 14.
    Besnard, P., Mercer, R., Schaub, T.: Optimality theory through default logic. In: Günter, A., Kruse, R., Neumann, B. (eds.) KI 2003. LNCS (LNAI), vol. 2821, pp. 93–104. Springer, Heidelberg (2003)Google Scholar
  15. 15.
    Brewka, G.: Adding priorities and specificity to Default Logic. In: Pereira, L., Pearce, D. (eds.) Proceedings of the 4th European Workshop on Logics in Articial Intelligence (JELIA-94), pp. 247–260 (1994)Google Scholar
  16. 16.
    Delgrande, J.P., Schaub, T.: Expressing preferences in Default Logic. Artificial Intelligence 123, 41–87 (2000)zbMATHCrossRefMathSciNetGoogle Scholar
  17. 17.
    Lifschitz, V.: On open defaults. In: Lloyd, J. (ed.) Computational Logic: Symposium Proceedings, pp. 80–95. Springer, Berlin (1990)Google Scholar
  18. 18.
    Kaminski, M.: A comparative study of open default theories. Artificial Intelligence 77, 285–319 (1995)zbMATHCrossRefMathSciNetGoogle Scholar
  19. 19.
    Charniak, E.: Motivation analysis, abductive unification and nonmonotonic equality. Artificial Intelligence 34, 275–295 (1988)CrossRefGoogle Scholar
  20. 20.
    Cohen, A., Makowsky, J.A.: Two approaches to nonmonotonic equality. Technical Report CIS-9317, Technion—Israel Institute of Technology (1993)Google Scholar
  21. 21.
    Cohen, A., Kaminski, M., Makowsky, J.A.: Indistinguishability by default. In: Artemov, S., et al. (eds.) We Will Show Them: Essays in Honour of Dov Gabbay, pp. 415–428. College Publications, London (2005)Google Scholar
  22. 22.
    Cohen, A., Kaminski, M., Makowsky, J.A.: Notions of sameness by default and their application to anaphora, vagueness, and uncertain reasoning. Ben-Gurion University and The Technion (2006)Google Scholar
  23. 23.
    Reiter, R.: Equality and domain closure in first order databases. Journal of the ACM 27, 235–249 (1980)zbMATHCrossRefMathSciNetGoogle Scholar
  24. 24.
    Heim, I.: The Semantics of Definite and Indefinite NPs. PhD thesis, University of Massachusetts at Amherst (1982)Google Scholar
  25. 25.
    Grice, H.P.: Logic and conversation. In: Cole, P., Morgan, J.L. (eds.) Syntax and Semantics 3: Speech Acts, Academic Press, London (1975)Google Scholar
  26. 26.
    Mendelson, E.: Introduction to mathematical logic. Chapman and Hall, London (1997)zbMATHGoogle Scholar
  27. 27.
    Clark, H.: Bridging. In: Johnson-Laird, P., Wason, P. (eds.) Thinking. Readings in Cognitive Science, pp. 411–420. Cambridge University Press, Cambridge (1977)Google Scholar

Copyright information

© Springer Berlin Heidelberg 2007

Authors and Affiliations

  • Ariel Cohen
    • 1
  1. 1.Ben-Gurion University, Beer Sheva 84105Israel

Personalised recommendations