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ISSUE-135 draft response

From: Sean Bechhofer <sean.bechhofer@manchester.ac.uk>
Date: Tue, 25 Nov 2008 08:41:21 +0000
Message-Id: <E3435932-C55F-4A12-9986-A7A7F94ED3E1@manchester.ac.uk>
To: SWD Working SWD <public-swd-wg@w3.org>

Hi all,

Here's a draft response to Michael on [ISSUE-135], let me know what you
think. Note *this is just a draft, not the actual response* -- I'll
wait for feedback from the WG before replying formally to
Michael.

Dear Michael

Thank you for your comments [1,ISSUE-135]:

"""
What is the rational for making SKOS labeling properties sub  
properties of
rdfs:label (besides the common name)? Note that rdfs:Label is an
owl:AnnotationProperty in OWL. While in OWL Full, annotation  
properties can have
sub properties, it looks at least a little odd (though formally fine)  
to have a
data property be a sub property of an annotation property. If no  
strong reasons
talk against, I suggest to /not/ have sub properties of rdfs:label.
"""

-------------------------------------------------------------

As you point out, the assertion does violate OWL DL constraints,  
although I'm
sure you are aware that this is not the only OWL DL constraint that  
is violated
by the current SKOS vocabulary.

In this particular case, a number of existing implementations (for  
example
linked data browsers) make use of rdfs:label in order to render  
resources.
Including the subproperty relation makes the SKOS lexical labels  
available to
such applications without any additional machinery beyond the RDF(S)  
semantics.

Your question suggests an alternate approach to this issue, however.  
In the
current schema, these are asserted to be instances of  
owl:DatatypeProperty. On
reflection, we feel that it is more appropriate to type these as
owl:AnnotationProperty (and retain the subproperty relationship.  
Although this
will still violate an OWL DL constriant (no subproperty relationships  
are
allowed on annotation properties), it is likely that changes in OWL 2  
will allow
relationships between annotation properties. It may then be possible to
represent SKOS in terms which conform to OWL 2 with minimal changes.

The Working Group thus propose to change the type of the SKOS labelling
properties to owl:AnnotationProperty, and *postpone* this issue  
(indicating that
it may merit further consideration in the future). Can you live with  
this?

Cheers,

	Sean Bechhofer
	Alistair Miles

[ISSUE-135] http://www.w3.org/2006/07/SWD/track/issues/135
[1] http://lists.w3.org/Archives/Public/public-swd-wg/2008Sep/0044.html

--
Sean Bechhofer
School of Computer Science
University of Manchester
sean.bechhofer@manchester.ac.uk
http://www.cs.manchester.ac.uk/people/bechhofer
Received on Tuesday, 25 November 2008 08:43:05 GMT

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