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Indirection

From: Miles, AJ \(Alistair\) <A.J.Miles@rl.ac.uk>
Date: Fri, 4 Feb 2005 16:44:15 -0000
Message-ID: <F5839D944C66C049BDB45F4C1E3DF89D18DB76@exchange31.fed.cclrc.ac.uk>
To: "Dan Brickley" <danbri@w3.org>
Cc: <public-esw-thes@w3.org>

Hi Dan, playing devil's advocate ...

> [[
> SKOS Core is an extension of the RDF model [ref], which is in turn an
> extension of the graph data model [ref]. For an explanation of these
> concepts, please refer to [ref]. The reader of this guide 
> should have at
> least a basic understanding of the RDF model and the graph data model.
> ]]
> 
> This needs a little rewrite. The term 'RDF model' is unfashionable, 
> post-RDFCore. It used to mean, roughtly, 'graph data model', but 
> now evokes Model Theory etc. SKOS isn't a 'semantic extension' to the 
> RDF model theory; this wording could give the impression it is. 

Why can't SKOS Core be a 'semantic extension' to the RDF model theory?

> It can be useful to
> understand the subtle, layered relationship between SKOS and RDF, 
> particularly when building applications that combine SKOS data with
> other information modeled using RDF.

Your gonna hate me, but ... 

> This is the SKOS approach. Technically, it creates an extra 
> layer of indirection, so that from the RDF point of view we are 
> describing things such as 'The concept of Economic 
> integration', rather 
> than <em>Economic integration<em> itself. 

... what's the difference?

Seriously, if I say ...

ex:A a skos:Concept.
ex:B a rdfs:Class.

... what fundamental commitments have I made about the natures of ex:A and ex:B?

And what if I say ...

ex:C a skos:Concept; a rdfs:Class.

... which inevitably will happen.  What does that mean?

***We need an answer on whether skos:Concept and rdfs:Class should be disjoint.***

If we don't make an explicit statement about this, they will be used as if they are not disjoint. 

And if we believe they should be disjoint, we need to be able to explain exactly what you gain by keeping them disjoint.

The 'two levels of abstraction' explanation is hard to grasp.  If we want to enforce two levels of abstraction, we're going to have to explain ourselves *extremely* well, and we're going to have to dangle a bloody big carrot.

Or have I just asked, 'can a person ever get out of their own head?'

Taoists need not respond :)

Al.
Received on Friday, 4 February 2005 16:44:47 GMT

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