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Re: personal LC comments on SKOS reference document

From: Sean Bechhofer <sean.bechhofer@manchester.ac.uk>
Date: Thu, 2 Oct 2008 11:56:52 +0100
Message-Id: <921742B5-F255-47B3-B23B-F170DE9D3D34@manchester.ac.uk>
Cc: public-swd-wg@w3.org
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>


Dear Peter,

Thanks for your comments and suggestions.

Your comments have been raised as the following issues: ISSUE-154,
ISSUE-155, ISSUE-156, ISSUE-157 and ISSUE-158. The Working
Group's issue tracker system is online at:

   http://www.w3.org/2006/07/SWD/track/

We hope to provide an initial response by Friday 10th October.

Yours,

	Sean Bechhofer

On 1 Oct 2008, at 19:42, Peter F. Patel-Schneider wrote:

>
> [These are personal comments, which may very quickly be overtaken by a
> closely related reply from the OWL WG.]
>
>
> Review of SKOS Reference last call document
> http://www.w3.org/TR/2008/WD-skos-reference-20080829/
>
> I would much prefer to have more formality in this reference document.
> I feel that it is important to have at least those parts of the SKOS
> model that fit into RDF or OWL be prominently mentioned.  It is true
> that there is a RDF/XML document that has the OWL 1 portion of  
> SKOS, but
> this is only mentioned at the very end of the reference document.  I
> feel that it would be much better to mention this RDF/XML document at
> the beginning of the reference document.  I also note that the  
> reference
> document mentions an outdated version of the RDF/XML document.
>
> I think that it would be very useful if there was a version of SKOS  
> that
> used OWL 2.  I understand that it is problematic for a  
> recommendation to
> point to something that is not (yet) a recommendation.  However, I  
> think
> that an informative document would be useful, even just a version  
> of the
> RDF/XML document that used the new OWL 2 features.  I think
> that it would be even more useful to have this information in another
> format, such as the OWL 2 reference syntax.
>
> One portion of SKOS (Notations) uses custom datatypes.  Although these
> seem to be benign, because RDF and OWL allow extra datatypes, the  
> use of
> these datatypes is not likely to be supported by many tools.  The
> presence of extra datatypes is likely to cause difficulties in some
> tools, which may just reject SKOS documents that have these datatypes.
>
> I would very much have liked more of SKOS to fit within OWL 2 DL.  I
> believe that many of the parts of SKOS that do not fit within OWL 2 DL
> are modelling errors.  To show what could be changed I have  
> performed an
> analysis (from the reference document, not from the RDF document)  
> of the
> bits of SKOS that are not in OWL 1 DL.  For those bits that are not in
> OWL 2 DL, I have suggestions on how SKOS could be changed to make  
> it fit
> within OWL 2 DL, where I could figure this out.  I believe that having
> as much of SKOS in OWL 2 DL would be of benefit to SKOS.  I note that
> many of the bits that are not OWL 2 DL are in examples, indicating  
> to me
> that they are not so central to SKOS.
>
> Section         Language        What bit / Suggestions to put into  
> OWL 2 DL
>
> skos:Concept    OWL 2 DL        individual/class/property punning  
> (examples)
>
> Concept Schemes OWL 2 DL        individual/ontology  
> "punning" (example)
>
> Lexical Labels  OWL 2 Full      subproperty of rdfs:label
>                                   suggestion: don't use rdfs:label
>
> 		OWL 2 DL	property disjointness
>
>                 not OWL         axiom schema for unique prefLabel
>                                   suggestion: include qualified
>                                   cardinality restrictions only
>                                   for languages used (defined using
>                                   datatype restrictions)
>
>                 OWL 2 DL        individual / class punning (example)
>
>                 OWL 2 Full      objects as values of data property  
> (example)
>                                   suggestion: don't do this
>
> Notations       extra datatypes	various extra datatypes
>                                   suggestion: sort of in OWL 1 DL
>  				  already, but unlikely to be supported
>                                   by many tools
>
> Documentation   OWL 2 Full      using literal in object property  
> (examples)
>                                   suggestion: don't do this
>
>                 OWL 2 Full      use of rdf:value (example)
>                                   suggestion: don't use rdf:value
>
>                 OWL 2 DL        individual/class punning (example)
>
> Semantic Rel's  OWL 2 DL        disjoint properties
>
> Concept Coll'ns OWL 2 Full      ordering with typing
>                                   suggestion: see below
>
> Mapping Props   OWL 2 DL        disjoint properties
>
> SKOS X          OWL 2 Full      data property chains
>      		      		 suggestion: ??
>
>
> Here is a way of handling typed ordering that should fit within OWL 2
> DL, although I haven't checked all the details.
>
> Declaration( ObjectProperty(skos:firstMember) )
> Declaration( ObjectProperty(skos:nextMembers) )
> Declaration( ObjectProperty(skos:otherMembers) )
> FunctionalProperty(skos:firstMember)
> FunctionalProperty(skos:nextMembers)
>
> PropertyDomain( skos:firstMember skos:OrderedCollection )
> PropertyRange( skos:firstMember UnionOf(skos:Concept  
> skos:ConceptScheme) ) ??
>
> PropertyDomain( skos:nextMembers skos:OrderedCollection )
> PropertyDomain( skos:nextMembers skos:OrderedCollection )
> PropertyDomain( skos:otherMembers skos:OrderedCollection )
> PropertyDomain( skos:otherMembers skos:OrderedCollection )
>
> SubPropertyOf( skos:nextMembers skos:otherMembers )
> SubPropertyOf( PropertyChain(skos:otherMembers skos:nextMembers)  
> skos:otherMembers )
>
> SubPropertyOf( skos:firstMember skos:member )
> SubpropertyOf( PropertyChain(skos:otherMembers skos:firstMember)  
> skos:member )
>
>
>
> Specific comments:
>
> The introduction uses some sophisticated Turtle constructs without  
> even
> any mention of the syntax being used.  At least a pointer is required
> here.
>
> Nits:
>
> "data are" vs "data does"
>
> counter-intuitive meaning -> counter-intuitive feeling
>

--
Sean Bechhofer
School of Computer Science
University of Manchester
sean.bechhofer@manchester.ac.uk
http://www.cs.manchester.ac.uk/people/bechhofer
Received on Thursday, 2 October 2008 10:56:46 GMT

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