SKOS Data Model as RDF Triples

Abstract

This document provides a reference to the SKOS RDF schema. The final version wil appear as an appendix to the SKOS Reference.

@@X. Appendix @@X. SKOS Data Model as RDF Triples

The SKOS data model expressed as RDF triples (in so far as possible) is given in the following resource:

• http://www.cs.man.ac.uk/~seanb/SKOS/schema/20080429/core.turtle (Turtle syntax)

@@X.1 Namespace

The SKOS Working Group are still considering the issue of the SKOS namespace (see ISSUE-117 [@@REF]). The schema above assumes the definition of a new namespace http://www.w3.org/2008/04/skos/core and makes no statements about deprecation of existing SKOS vocabulary. The Working Group may make a decision that a new namespace is not to be defined. In that case, the schema may also include information about deprecation.

@@X.2 Schema as OWL Ontology

This RDF schema defines an OWL ontology. SKOS vocabularies can then be defined as instances of this ontology. Note that as the schema violates some of the constraints on OWL DL ontologies, this ontology is an OWL Full Ontology [@@REF]. In particular, some documentation properties are defined as owl:ObjectProperty and then used with data values. SKOS documentation properties are defined as instances of owl:ObjectProperty and are then used to state properties of classes within the SKOS vocabulary. Both of these situations violate the requirement that the namespaces of classes, properties and individuals are kept separated in OWL DL ontologies.

W3C's OWL WG [@@REF] are producing a recommendation that refines and extends OWL. It is likely that the OWL 2 recommendations will accommodate the kinds of modelling used in the SKOS Schema. In that event, the RDF schema may be updated to take this into account — we do not envisage that this will result in significant changes to the underlying interpretations of the SKOS vocabulary, rather a re-presentation of the schema in order to provide an OWL 2-friendly version.

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