RE: Defining a property to have an EMPTY range?

Surely the obvious way is to have an owl:Class Secret, to which all secret
documents can belong.  I took Roger to be asking for a unary predicate, and
class membership is the only unary predicate defined in RDF. 

This would also make it nice and easy for semantic web agents to search for
secret documents :-)

Cheers,
Ian


> -----Original Message-----
> From: Jon Hanna [mailto:jon@spin.ie] 
> Sent: 14 May 2003 13:50
> To: www-rdf-interest@w3.org
> Subject: RE: Defining a property to have an EMPTY range?
> 
> 
> 
> > Example: I would like to be able to "tag" a Document with a 
> security 
> > classification, e.g.,
> >
> >    <Document>
> >        <secret/>
> >        <content>
> >            ...
> >        </content>
> >    </Document>
> >
> > Note the <secret/> property.  Its purpose it simply to "tag" this 
> > Document as having a secret classification.
> 
> Think about what that would be in triples:
> 
> <DocumentURI> <secret> <EMPTY> .
> 
> Hardly seems correct. Indeed it isn't valid RDF/XML.
> What's more the lack of the <secret/> element in the Document 
> doesn't preclude the possibility that it has the same status 
> as one with a <secret/> element (given RDFs open nature).
> 
> I think you are applying a XML document design technique to 
> RDF/XML that doesn't belong in RDF/XML.
> 
> One option is to continue to do so, in particular if RDF 
> isn't the main thing you are doing with this document. It 
> would still be possible to represent that a document has a 
> confidentiality status of "secret" in RDF by other means if 
> necessary (perhaps at a different level in the application).
> 
> On the other hand if RDF is a major part of what you are 
> doing here then something like:
> 
> <Document>
>  <secret>true</secret>
>  <content>...</content>
> </Document>
> 
> or
> 
> <Document>
>  <securityLevel rdf:resource="http://someURI/security#secret"/>
>  <content>...</content>
> </Document>
> 
> might be more appropriate.
>

Received on Wednesday, 14 May 2003 09:06:25 UTC