Section 3 of OWL 2 Web Ontology Language: Structural Specification and Functional-Style Syntax says: http://www.w3.org/TR/2008/WD-owl2-syntax-20080411/#Ontologies [[ OWL 2 allows each axiom to contain annotations. These can be used to associate arbitrary information with an axiom. This information does not affect the semantics of the language in any way. ]] But Section 2.1 of OWL 2 Web Ontology Language: Mapping to RDF Graphs says: http://www.w3.org/TR/2008/WD-owl2-mapping-to-rdf-20080411/#Annotated_Axioms [[ Axioms with annotations are reified. If s p o is the RDF serialization of the corresponding axiom without annotations given in Table 2 and the axiom contains annotations Annotation(apIDi cti), 1 ˜ i ˜ n, then, instead of being serialized as s p o, the axiom is serialized as follows . . . . ]] In other words, from a strictly OWL 2 perspective, the reified axioms (apparently) still carry the same semantics as the non-reified axioms. However, from an RDF perspective there is an enormous difference: an annotation causes the axioms to disappear! Given that the axioms are usually the main point of OWL/RDF statements -- though of course this is a subjective -- it seems quite unfortunate that they disappear by the mere addition of an annotation. Have I understood this correctly? If so, this looks to me like it would be a significant problem in making OWL 2 work well with other RDF, as RDF is combined from multiple sources, some of which might have orginally been OWL 2. David Booth, Ph.D. HP Software +1 617 629 8881 office | dbooth@hp.com http://www.hp.com/go/software Statements made herein represent the views of the author and do not necessarily represent the official views of HP unless explicitly so stated.Received on Tuesday, 22 July 2008 02:05:11 GMT
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