- From: Antoine Isaac <aisaac@few.vu.nl>
- Date: Sun, 22 Mar 2009 17:17:42 +0100
- To: Ivan Herman <ivan@w3.org>
- CC: SWD WG <public-swd-wg@w3.org>
Hi Ivan, Thank you very much for the feedback! That's a great help. I note the RDF examples of [1], but still miss the RDF/XML version ;-) Cheers, Antoine > 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/ >> >> >
Received on Sunday, 22 March 2009 16:18:22 UTC