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Representation of Partial Knowledge and Query Answering in Locally Complete Databases

  • Álvaro Cortés-Calabuig
  • Marc Denecker
  • Ofer Arieli
  • Maurice Bruynooghe
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4246)

Abstract

The Local Closed-World Assumption (LCWA) is a generalization of Reiter’s Closed-World Assumption (CWA) for relational databases that may be incomplete. Two basic questions that are related to this assumption are: (1) how to represent the fact that only part of the information is known to be complete, and (2) how to properly reason with this information, that is: how to determine whether an answer to a database query is complete even though the database information is incomplete. In this paper we concentrate on the second issue based on a treatment of the first issue developed in earlier work of the authors. For this we consider a fixpoint semantics for declarative theories that represent locally complete databases. This semantics is based on 3-valued interpretations that allow to distinguish between the certain and possible consequences of the database’s theory.

Keywords

Relational Database Predicate Symbol Partial Knowledge Ground Atom Deductive Database 
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

  • Álvaro Cortés-Calabuig
    • 1
  • Marc Denecker
    • 1
  • Ofer Arieli
    • 2
  • Maurice Bruynooghe
    • 1
  1. 1.Department of Computer ScienceKatholieke Universiteit LeuvenBelgium
  2. 2.Department of Computer ScienceThe Academic College of Tel-AvivIsrael

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