A proposal for an owl rules language

ABSTRACT

Although the OWLWeb Ontology Language adds considerable expressive power to the Semantic Web it does have expressive limitations, particularly with respect to what can be said about properties. Wepresent ORL (OWL Rules Language), a Horn clause rules extension to OWL that overcomes many of these limitations. ORL extends OWL in a syntactically and semantically coherent manner: the basic syntax for ORL rules is an extension of the abstract syntax for OWL DL and OWLLite; ORL rules are given formal meaning via an extension of the OWLDL model-theoretic semantics; ORL rules are given an XML syntax basedon the OWL XML presentation syntax; and a mapping from ORL rules to RDF graphs is given based on the OWL RDF/XML exchange syntax. Wediscuss the expressive power of ORL, showing that the ontology consistency problem is undecidable, provide several examples of ORLusage, and discuss how reasoning support for ORL might be provided.

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INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE
      I.2.4 Knowledge Representation Formalisms and Methods
          Subjects: Representation languages

Additional Classification:
  F. Theory of Computation
  F.4 MATHEMATICAL LOGIC AND FORMAL LANGUAGES
      F.4.1 Mathematical Logic
          Subjects: Model theory

General Terms:
Languages, Theory

Keywords:
model-theoretic semantics, representation, semantic web