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RE: ISSUE-64: TextualDescriptionsForConcepts

From: Miles, AJ \(Alistair\) <A.J.Miles@rl.ac.uk>
Date: Tue, 20 Nov 2007 17:06:40 -0000
Message-ID: <677CE4DD24B12C4B9FA138534E29FB1D03B3F228@exchange11.fed.cclrc.ac.uk>
To: "SWD WG" <public-swd-wg@w3.org>

Btw, just to explain a small point about the new section I added to the SKOS Reference on documentation properties [1] ...

I said that I wrote this section to be exactly the same as what we had before in the SKOS Core Guide [2]. However, you may have noticed that the first semantic condition states that these properties have type owl:ObjectProperty. 

This statement was not in the original SKOS Core specifications. However, I was following the design principle that, in the SKOS Reference, every URI in the SKOS vocabulary is given an explicit OWL type (either Class, Object Property or Datatype Property). In the original specification, the type of the SKOS documentation properties is rdf:Property. In the RDF-compatible OWL Full semantics, rdf:Property is equivalent to owl:ObjectProperty. So actually, this statement is not new after all.

Also, at first glance, this statement would seem to contradict the "documentation as an RDF literal" pattern. However, again, note that in the OWL Full semantics, owl:ObjectProperty is equivalent to rdf:Property, and that owl:DatatypeProperty is a sub-class of owl:ObjectProperty. Therefore, stating the type to be owl:ObjectProperty is actually the weakest statement you can make, and is consistent with all three documentation property usage patterns.

Of course, under an OWL-DL interpretation, this statement would only be consistent with the second and third usage patterns, because Datatype Properties and Object Properties are disjoint in the OWL-DL universe. So the usage patterns would have to be restricted in some way to remain within OWL-DL. Although we have post-poned the issue of OWL-DL compatibility, this is one reason why our choice to allow 3 different usage patterns might be reconsidered. Also, this is the kind of thing that a section on using SKOS within OWL-DL could address.

Cheers,

Alistair. 

> -----Original Message-----
> From: public-swd-wg-request@w3.org 
> [mailto:public-swd-wg-request@w3.org] On Behalf Of Miles, AJ 
> (Alistair)
> Sent: 20 November 2007 13:36
> To: SWD WG
> Subject: RE: ISSUE-64: TextualDescriptionsForConcepts
> 
> 
> Hi all,
> 
> I've added a new section to the SKOS Reference wiki draft:
> 
> [1] <http://www.w3.org/2006/07/SWD/wiki/SKOS/Reference/Documentation>
> 
> This section defines the formal semantics of the SKOS 
> documentation (note) properties.
> 
> I've written this section to be faithfully the same as the 
> previous specifications given in the SKOS Core Guide [2] -- 
> I.e. this is just what we had before.
> 
> I've also raised an issue (see below) asking whether we 
> should revisit the design of these properties. Documentation 
> (note) properties are an important part of SKOS, so I suggest 
> we make this a high priority issue.
> 
> I'd also like to talk about multimedia content in 
> documentation properties, but I'll put that in a separate issue.
> 
> Cheers,
> 
> Al.
> 
> 
> [2] 
> <http://www.w3.org/TR/2005/WD-swbp-skos-core-guide-20051102/#s
> ecdocumentation>
> 
> 
> > -----Original Message-----
> > From: public-swd-wg-request@w3.org
> > [mailto:public-swd-wg-request@w3.org] On Behalf Of SWD Issue Tracker
> > Sent: 20 November 2007 13:15
> > To: public-swd-wg@w3.org
> > Subject: ISSUE-64: TextualDescriptionsForConcepts
> > 
> > 
> > 
> > ISSUE-64: TextualDescriptionsForConcepts
> > 
> > http://www.w3.org/2006/07/SWD/track/issues/64
> > 
> > Raised by: Alistair Miles
> > On product: SKOS
> > 
> > SKOS currently has 7 "documentation"/"note" properties: 
> > skos:note, skos:scopeNote, skos:defition, skos:historyNote, 
> > skos:editorialNote, skos:changeNote, skos:example.
> > 
> > In the SKOS Core Guide
> > <http://www.w3.org/TR/2005/WD-swbp-skos-core-guide-20051102>,
> > 3 different design patterns are allowed for these properties
> > -- "documentation as an RDF literal", "documentation as a related 
> > resource description", and "documentation as a document reference".
> > 
> > Do we continue to allow these different design patterns? If 
> we do, we 
> > have to accept a complex range for these properties. Is 
> that OK? How 
> > should we formally specify that?
> > 
> > 
> > 
> > 
> > 
> > 
> 
> 



--
Alistair Miles
Research Associate
Science and Technology Facilities Council
Rutherford Appleton Laboratory
Harwell Science and Innovation Campus
Didcot
Oxfordshire OX11 0QX
United Kingdom
Web: http://purl.org/net/aliman
Email: a.j.miles@rl.ac.uk
Tel: +44 (0)1235 445440  
Received on Tuesday, 20 November 2007 17:06:53 UTC

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