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RE: [Proposal][SKOS-Core] skos:denotes

From: Miles, AJ (Alistair) <A.J.Miles@rl.ac.uk>
Date: Fri, 1 Oct 2004 11:57:06 +0100
Message-ID: <350DC7048372D31197F200902773DF4C05E50C54@exchange11.rl.ac.uk>
To: "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>

How about this for an argument as to why resources of type skos:Concept are
at a different level of abstraction to, say for example, resources of type
foaf:Person ... 

You would not say that a 'scopeNote' or a 'definition' is a property of a

However, you might reasonably say that an 'email address' or 'date of birth'
is a property of a person.


Alistair Miles
Research Associate
CCLRC - Rutherford Appleton Laboratory
Building R1 Room 1.60
Fermi Avenue
Oxfordshire OX11 0QX
United Kingdom
Email:        a.j.miles@rl.ac.uk
Tel: +44 (0)1235 445440

> -----Original Message-----
> From: public-esw-thes-request@w3.org
> [mailto:public-esw-thes-request@w3.org]On Behalf Of Dave Reynolds
> Sent: 30 September 2004 18:38
> To: Matthews, BM (Brian) 
> Cc: 'public-esw-thes@w3.org'
> Subject: Re: [Proposal][SKOS-Core] skos:denotes
> Matthews, BM (Brian) wrote:
> > As I interpret this,  this gives the best semantics I know of for 
> > Thesaurus concepts - a concept's denotation is "the set of 
> resources 
> > which are classified under that concept" (my words).  This is quite 
> > different from the intended use in Ontologies, where instances are 
> > "supposed" to stand for "real-world" things (with suitable 
> philosophical 
> > quotation marks).
> I agree with that summary of the semantics of Thesaurus 
> concepts but I'm 
> not so sure ontologies are that different. Sure in 
> philosophical terms 
> ontologies are more than that, as you say, but in practical 
> RDFS and OWL 
> terms a class is just a set of instances and an instance is just a 
> "resource". It so happens that OWL gives you some machinery 
> for identifying 
> the class of a resource by its properties, and RDFS gives you 
> less, but the 
> difference between those and your semantics for Thesaurus 
> concepts is just 
> a matter of expressivity rather than of fundamental nature.
> Personally I find this article nicely captures this view that 
> they are just 
> a continuum with different expressivity and degree of formality:
> http://www.metamodel.com/article.php?story=20030115211223271
> > So I think that the word "denotes" to connect a 
> thesaurus-theoretic and
> > a ontology-theoretic point of view is dangerous - as in logic
> > and mathematics this usually signifies semantics - we are 
> not (should
> > not) be saying that the class provides a semantics for the concept.
> Agreed.
> > An alternative term then?  skos:classifierFor is perhaps 
> most precise,
> > though a bit awkward.  But I prefer it to the alternatives we have
> > seen so far which imply some kind of semantic relationship.
> To me that also implies a semantic relationship but maybe 
> that's just me.
> > Nikki says:
> > 
> >>Or is this debate really about the fact that we want to stick some 
> >>machinery capable of SKOS<->OWL stuff in SKOS-Core right 
> now, so that 
> >>SKOS-Core stands in its own right allowing us to tackle 
> SKOS-Mapping 
> >>separately?
> > 
> > 
> > As far as I see - yes!  The use of this property is to do 
> the modelling
> > task of relating SKOS and OWL - and SKOS-mapping should be separate.
> To me there's no particular difference between saying that two SKOS 
> Concepts are trying to model the same "real world" thing and 
> saying that a 
> SKOS Concept and an OWL Class are trying to model the same 
> "real world" 
> thing. So I'm with Nikki, it seems odd putting it in the core 
> rather than 
> in mapping.
> > To turn to the specifics of the proposal (to start a new 
> controversy),
> > does it make sense (particularly when taking a point of view that
> > we are providing a classifier for an RDF resource) for this property
> > to be a functional property?  This would mean if two 
> resources have the
> > same classifier, they can be identified.  This may not make sense.
> My vote would be "no".
> For example, you might have a SKOS Thesaurus concept 
> "my:Person" an RDF 
> Class foaf:Person and an RDF Class drc:Person. They are all 
> trying to model 
> the same real world notion but in different ways (e.g. 
> drc:Person might 
> have cardinality restrictions on properties that foaf:Person 
> has nothing to 
> do with). As I understand it, the point of this property is 
> to be able to 
> say "my:Person and foaf:Person are both attempts to model the 
> same thing" 
> without carrying any semantics such as cardinality restrictions.
> It would be reasonable to also want to say "my:Person and 
> drc:Person are 
> both attempts to model the same thing" without that implying that 
> drc:Person = foaf:Person (with all that would entail from the formal 
> semantics of the foaf and drc schemas).
> Cheers,
> Dave
Received on Friday, 1 October 2004 10:57:39 UTC

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