- From: Ivan Herman <ivan@w3.org>
- Date: Fri, 20 Mar 2009 14:28:39 +0100
- To: Antoine Isaac <aisaac@few.vu.nl>
- CC: SWD WG <public-swd-wg@w3.org>
- Message-ID: <49C39A07.2010006@w3.org>
Antoine, a heroic effort with a moving target:-) Just a few pointers that may help: - the editor's draft of the Syntax document for OWL 2[1] includes all the examples in RDF, too. There is a set of buttons at the beginning of the document where you can select which syntax you want to see for the examples. Maybe that helps... - it is indeed true that the core functional syntax for OWL 2 does not define the usage of property disjointness for annotation properties. However, in the RDF compatible semantics of OWL 2 (essentially, OWL 2 Full), propertyDisjointWith is defined on _any_ property, ie, it provides the necessary semantics for disjoint annotation properties, too. Disjointness of annotation properties as a requirement never came to the OWL 2 group, to be honest... - as an answer to one of the LC comments, the RDF encoding of property chains have changed. In the final version of OWL 2 the encoding of your axiom should be (in turtle): skos:prefLabel owl:propertyChainAxiom (skos:prefLabel skos:literalForm). Cheers Ivan [1] http://www.w3.org/2007/OWL/wiki/Syntax [2] http://www.w3.org/2007/OWL/wiki/RDF-Based_Semantics Antoine Isaac wrote: > Hi, > > I have given a try at creating OWL 2 axioms for representating our > non-formally stated axioms in skos.rdf and [1] for skos-xl.rdf [2], see > below. > > I found it in fact really more difficult than planned, and the lack of > RDF/XML examples in OWL2 is really an obstacle. > > Anyway, it seems a good idea to already be aware right now of the issues > that we could have later... > > I hope this will help, > > Antoine > > ================== > > S12. The rdfs:range of each of skos:prefLabel, skos:altLabel and > skos:hiddenLabel is the class of RDF plain literals. > > At first sight this axiom could represented using rdf:Text. [3] reads: >> The datatype identified by the URI >> http://www.w3.org/1999/02/22-rdf-syntax-ns#text (abbreviated rdf:text) >> allows for the representation of internationalized text strings. In >> addition to the RIF and OWL specifications, this datatype is expected >> to supersede RDF's plain literals with language tags > > However, I would not recommend to use it until the "expectations" have > been met, and RDF plain literals indeed been superseded. > > ================== > > S13. skos:prefLabel, skos:altLabel and skos:hiddenLabel are pairwise > disjoint > > Here is a first try at an RDF/XML representation of this axiom: > > <owl:ObjectProperty rdf:about="#prefLabel"> > <owl:propertyDisjointWith rdf:resource="#altLabel"/> > <owl:propertyDisjointWith rdf:resource="#hiddenLabel"/> > </owl:ObjectProperty> > <owl:ObjectProperty rdf:about="#altLabel"> > <owl:propertyDisjointWith rdf:resource="#hiddenLabel"/> > </owl:ObjectProperty> > > > However I'm not sure this would be ok, as [4] hints at applying it > either to object properties or datatype properties, but says nothing on > annotation properties... > > Indeed I tried to create the axiom using Protégé 4. It assumed that > prefLabel, altLabel and hiddenLabel were instances of DatatypeProperty, > and represented my axioms as: > <owl:disjointObjectProperties rdf:resource="#hiddenLabel"/> > But apparently this owl:disjointObjectProperties construct does not > exist in the RDF mapping at [5]! > > Note that OWL 2 also allows for group declaration of disjoint > properties. But given that we only have three disjoint properties, and > that group disjointness seems cumbersome to represent in RDF syntax (it > requires using owl:AllDisjointProperties, and an owl:members which > intuitively conflicts with rdf:member the same way as our own > skos:member does :-/ ), I'd recommend to keep to the simple construct. > > > ================== > > S14. A resource has no more than one value of skos:prefLabel per > language tag. > > This cannot be expressed. > > ================= > > S27. skos:related is disjoint with skos:broaderTransitive > > With the same caveats as for S13 (my Protégé had used > owl:disjointObjectProperties), we can represent this axiom by: > > <owl:ObjectProperty rdf:about="#related"> > <owl:propertyDisjointWith rdf:resource="#broaderTransitive"/> > </owl:ObjectProperty> > > ================= > > S36. For any resource, every item in the list given as the value of the > skos:memberList property is also a value of the skos:member property > > This axiom cannot be represented, unless we first introduce an auxiliary > propery that allows a direct access to the object of the rdf:rest > statement in the definition of the member list. > > ================= > > S46. skos:exactMatch is disjoint with each of the properties > skos:broadMatch and skos:relatedMatch. > > With the same caveats as for S13, we can represent this axiom by: > > <owl:ObjectProperty rdf:about="#exactMatch"> > <owl:propertyDisjointWith rdf:resource="#broadMatch"/> > <owl:propertyDisjointWith rdf:resource="#relatedMatch"/> > </owl:ObjectProperty> > > > ============ SKOS-XL > > S51. The range of skosxl:literalForm is the class of RDF plain literals. > > Cf S12. > > ================= > > S55. If C skosxl:prefLabel L and L skosxl:literalForm V, then X > skos:prefLabel V. > > <rdf:Description> > <rdfs:subPropertyOf > rdf:resource="http://www.w3.org/2004/02/skos/core#prefLabel"/> > <owl:propertyChain rdf:parseType="Collection"> > <rdf:Description > rdf:about="http://www.w3.org/2008/05/skos-xl#prefLabel"/> > <rdf:Description > rdf:about="http://www.w3.org/2008/05/skos-xl#literalForm"/> > </owl:propertyChain> > </rdf:Description> > > > > ================= > > S56. If C skosxl:altLabel L and L skosxl:literalForm V, then X > skos:altLabel V. > > <rdf:Description> > <rdfs:subPropertyOf > rdf:resource="http://www.w3.org/2004/02/skos/core#altLabel"/> > <owl:propertyChain rdf:parseType="Collection"> > <rdf:Description > rdf:about="http://www.w3.org/2008/05/skos-xl#altLabel"/> > <rdf:Description > rdf:about="http://www.w3.org/2008/05/skos-xl#literalForm"/> > </owl:propertyChain> > </rdf:Description> > > > ================= > > S57. If C skosxl:hiddenLabel L and L skosxl:literalForm V, then C > skos:hiddenLabel V. > > <rdf:Description> > <rdfs:subPropertyOf > rdf:resource="http://www.w3.org/2004/02/skos/core#hiddenLabel"/> > <owl:propertyChain rdf:parseType="Collection"> > <rdf:Description > rdf:about="http://www.w3.org/2008/05/skos-xl#hiddenLabel"/> > <rdf:Description > rdf:about="http://www.w3.org/2008/05/skos-xl#literalForm"/> > </owl:propertyChain> > </rdf:Description> > > ============== > > > [1] http://www.w3.org/2006/07/SWD/SKOS/reference/20081001/skos.rdf > [2] http://www.w3.org/2006/07/SWD/SKOS/reference/20081001/skos-xl.rdf > [3] http://www.w3.org/TR/2008/WD-rdf-text-20081202/ > [4] http://www.w3.org/TR/2008/WD-owl2-quick-reference-20081202/ > [5] http://www.w3.org/TR/2008/WD-owl2-mapping-to-rdf-20081202/ > > -- Ivan Herman, W3C Semantic Web Activity Lead Home: http://www.w3.org/People/Ivan/ mobile: +31-641044153 PGP Key: http://www.ivan-herman.net/pgpkey.html FOAF: http://www.ivan-herman.net/foaf.rdf
Received on Friday, 20 March 2009 13:28:29 UTC