RE: Comments on SKOS Reference

Dear Tom,

A new Editors' Draft of the SKOS Reference is available at:

[1] <>

This new draft attempts to address your comment below as follows.

An editorial note has been added in section 1.6.1. (Formal Definitions) explaining that the WG is considering other ways of stating the formal definitions, with a link through to ISSUE-67.

As a temporary fix for your specific comments below, and following some of the suggestions made on this list, the style of the formal definitions given throughout the document has been changed, and now follows the style of prose used in the RDFS spec <>. This is explained with some examples in section 1.6.1.

Kind regards,


> -----Original Message-----
> From: 
> [] On Behalf Of Thomas Baker
> Sent: 03 January 2008 10:05
> To: SWD Working Group
> Subject: Comments on SKOS Reference
> Alistair, Sean, all,
> I hope everyone is having restful holidays.  
> I have been studying the new draft SKOS Reference [1], which 
> pulls together and summarizes the design decisions taken 
> since Amsterdam.  Kudos to Alistair and Sean for this 
> substantial piece of work!
> As noted in Section 1.1, some of the explanatory bits are a 
> bit long and should perhaps eventually be moved to the 
> Primer, but we need to first agree on what those explanations 
> should say so this is the right place to park them for now.  
> Telling the story on how SKOS relates to ontologies is 
> especially crucial.
> For now, just one general comment.  
> I happened to start reading the document somewhere in the 
> middle and found the informal prose presentation of the model 
> -- e.g., "skos:ConceptScheme has type Class" (4.3) -- a bit 
> disorienting.  As a reader I found myself flipping back to 
> the Introduction for an explanation. Section 1.5 says that 
> the prose is used "to improve the overall readability of this 
> document, rather than mix RDF triples and other notations"; 
> that "the meaning of this prose will be obvious to a reader 
> with a working knowledge of RDF and OWL"; and that "Class"
> means "owl:Class", etc. This tells me enough to interpret the 
> above as "skos:ConceptScheme rdf:type owl:Class".  Then I 
> noted that there is a placeholder in Appendix C for the SKOS 
> data model as RDF triples.
> In my recollection, we decided in Amsterdam to use prose in 
> order to avoid putting formulations such as
>     For any resource x, all members of the set { y | <x,y>
>     is in IEXT(I(skos:prefLabel)) } are RDF plain literals
>     and no two members of this set share the same language tag.
> into the body of the spec -- i.e., for constraints that 
> cannot be expressed as triples.  
> I'm wondering if we really gain readability by rendering the 
> triples themselves as prose. Will there be many readers who 
> _do_ understand "has type Class" but do _not_ understand 
> "rdf:type owl:Class" (or simply read it as "rdf:type 
> rdfs:Class")?  Is it possible, on the other hand, that an 
> inexpert reader could get confused by formulations such as 
> "The Domain and Range of...", not realizing it is a shorthand 
> for "The Domain of..." and "The Range of..."?
> My preference would be to see the components of the model, 
> whenever possible, in triples, and that Appendix C be 
> reserved for other types of formalisms (such as the above).
> In order to improve readability for readers who are not used 
> to reading triples, the triples could perhaps be restated as 
> prose -- but then they could be worded in ways that are 
> unconstrained by the need to make the mapping obvious, e.g., 
> "skos:ConceptScheme is an instance of the class owl:Class".
> I suggest that everyone take the time now to give this key 
> new draft a careful read.
> All the best in the New Year,
> Tom
> [1]
> --
> Thomas Baker <> W3C Semantic Web 
> Deployment Working Group

Alistair Miles
Research Associate
Science and Technology Facilities Council Rutherford Appleton Laboratory Harwell Science and Innovation Campus Didcot Oxfordshire OX11 0QX United Kingdom
Tel: +44 (0)1235 445440  

Received on Friday, 18 January 2008 16:46:07 UTC