Implementing query answering for hybrid MKNF knowledge bases

Ana Sofia Gomes, José Júlio Alferes, Terrance Swift

Research output: Chapter in Book/Report/Conference proceedingConference contribution

14 Scopus citations


Ontologies and rules are usually loosely coupled in knowledge representation formalisms. In fact, ontologies use open-world reasoning while the leading semantics for rules use non-monotonic, closed-world reasoning. One exception is the tightly-coupled framework of Minimal Knowledge and Negation as Failure (MKNF), which allows statements about individuals to be jointly derived via entailment from an ontology and inferences from rules. Nonetheless, the practical usefulness of MKNF has not always been clear, although recent work has formalized a general resolution-based method for querying MKNF when rules are taken to have the well-founded semantics, and the ontology is modeled by a general Oracle. That work leaves open what algorithms should be used to relate the entailments of the ontology and the inferences of rules. In this paper we provide such algorithms, and describe the implementation of a query-driven system, CDF-Rules, for hybrid knowledge bases combining both (non-monotonic) rules under the well-founded semantics and a (monotonic) ontology, represented by a CDF (ALCQ) theory.

Original languageEnglish (US)
Title of host publicationPractical Aspects of Declarative Languages - 12th International Symposium, PADL 2010, Proceedings
PublisherSpringer Verlag
Number of pages15
ISBN (Print)3642115020, 9783642115028
StatePublished - 2010
Externally publishedYes
Event12th International Symposium on Practical Aspects of Declarative Languages, PADL 2010 - Madrid, Spain
Duration: Jan 18 2010Jan 19 2010

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume5937 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Other12th International Symposium on Practical Aspects of Declarative Languages, PADL 2010

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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