Re: Importing SKOS model in ontology editors : clash with annotation properties

Bernard, Johannes

The OWL Full/DL issue was discussed in the WG (see, e.g. ISSUE-38  
[1]). During the LC period, the WG took a decision to change the  
typing of labelling and documentation properties to be Annotation  
Properties (see also discussion concerning resolution of ISSUE-157  
[2]). Although the presence of subproperty assertions between the  
labels and rdf:label and and the documentation properties and  
skos:note violate the DL constraints, it was our understanding that  
OWL 2 would move towards supporting subproperty relationships between  
annotation properties. Adopting this design will hopefully minimise  
potential changes in the future in order to provide an OWL2-DL  
conformant vocabulary (personally, I also believe that defining those  
properties as annotation properties is also more appropriate).

> Here you point to such a prune candidate:
> > http://www.w3.org/2006/07/SWD/SKOS/reference/20081001/skos-dl.rdf

I have regenerated the "DLised version" of the SKOS vocabulary [3].  
The version is produced by removing some of the axioms that violate  
the DL constraints, in particular, those axioms relating to the  
subproperty assertions concerning labelling and documentation  
properties. This is a similar approach to that you discussed for the  
geonames. Note that this does *not* form part of the SKOS  
recommendation, but may be of some use in tools (it was originally  
done to support some tooling being developed by Simon Jupp [4]).

> I have fed this to
> - http://www.mygrid.org.uk/OWL/Validator
> which gives back OWL DL plus some minor errors ("Possibly using  
> wrong vocabulary (rdf:Property instead of owl:[Object|Data] 
> Property)...")

These aren't errors, but are rather warnings. They are generated  
because the SKOS vocabulary contains (redundant) assertions about  
properties. For example, there are triples that state:

skos:inScheme rdf:type owl:ObjectProperty.
skos:inScheme rdf:type rdf:Property.

These redundant triples were included to support non OWL aware  
applications [5].

> Then we have a first question:
> - Would the editors of SKOS agree that this (or a similar) OWL DL  
> subset   reflects most of their *intended* semantic?

Speaking personally, yes (and I would hope so as I generated it :-).  
As discussed above, it is missing the subproperty assertions (and  
other statements concerned with metadata -- dc/dct vocabulary), but  
in so far as it is possible to produce a SKOS OWL DL vocabulary, I  
believe it to be a good fit.

Cheers,

	Sean

[1] http://www.w3.org/2006/07/SWD/track/issues/38
[2] http://www.w3.org/2006/07/SWD/track/issues/157
[3] http://www.w3.org/2006/07/SWD/SKOS/reference/20090315/skos-dl.rdf
[4] http://code.google.com/p/skoseditor/
[5] http://www.w3.org/2008/11/18-swd-minutes.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 Wednesday, 25 March 2009 12:05:09 UTC