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

From: Miles, AJ (Alistair) <A.J.Miles@rl.ac.uk>
Date: Fri, 1 Oct 2004 13:40:24 +0100
Message-ID: <350DC7048372D31197F200902773DF4C05E50C59@exchange11.rl.ac.uk>
To: "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>



I think what I meant was ...

If we have two resources:

ex:resourceA	a	skos:Concept;
				skos:prefLabel	'Alistair Miles';
				skos:scopeNote	'My mate Al.'
.

ex:resourceB	a	foaf:Person;
				foaf:name	'Alistair Miles';
				foaf:mbox	<mailto:a.j.miles@rl.ac.uk>
.

... the burining questions are:

Are these two resources fundamentally different in nature, or not?

Are these two resources at different levels of abstraction, or not?

My point in the last email [1] was that, it *does not* seem reasonable to
allow for example:

ex:resourceC	a	skos:Concept;
				skos:prefLabel	'Alistair Miles';
				skos:scopeNote	'My mate Al.';
				a	foaf:Person;
				foaf:name	'Alistair Miles';
				foaf:mbox	<mailto:a.j.miles@rl.ac.uk>
.

... intuitively because properties like 'skos:scopeNote' seem appropriate to
describe an abstract concept, but not to describe a person.

I.e. in logic speak the classes skos:Concept and foaf:Person should be
disjoint.  

What Dave said in an earlier email (I think) was that I should not think of
ex:resourceB as an actual person, but as an abstract entity, with the same
metaphysical status as ex:resourceA (i.e. they are both abstractions).

But intuitively I do think of ex:resourceB as an actual person (should I
change that?), and that feeling is the basis for my assertion above.  And
even if I do accept they are both abstractions, one *feels* to me more
abstract than the other.

Are we getting closer or farther away?

Al. 

[1] http://lists.w3.org/Archives/Public/public-esw-thes/2004Oct/0000.html

---
Alistair Miles
Research Associate
CCLRC - Rutherford Appleton Laboratory
Building R1 Room 1.60
Fermi Avenue
Chilton
Didcot
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 NJ 
> Rogers, Learning
> and Research Technology
> Sent: 01 October 2004 12:36
> To: Miles, AJ (Alistair); 'public-esw-thes@w3.org'
> Subject: RE: [Proposal][SKOS-Core] skos:denotes
> 
> 
> 
> Ok, so you're talking about the class/instance issue, right?
> 
> You're saying that OWL classes and foaf classes for example 
> can be used in 
> the range of the rdf type property. So that a resource may be 
> of *type* 
> person.
> And you're saying that naturally skos Concept *instances* (e.g. 
> myskos:Person - a skos concept that represents the concept of 
> a Person 
> (?!)) can*not* be used in the range of the rdf type property.
> 
> So you're saying, for these cases, that in order to indicate e.g. a 
> foaf:Person (class) has some association with 
> e.g.myskos:Person (instance) 
> we need a skos:denotes property in SKOS Core.
> 
> I get this logic. But I still don't get why this is machinery is so 
> important. When do we want to query RDF data in a way such 
> that we need 
> skos:denotes? It must be blindingly obvious, but please point 
> it out to me, 
> gimme an example!!
> 
> /me thinks further: is it that we might want to phrase RDF 
> queries such 
> that we effectively ask "this foaf:Person class, what concept does it 
> relate to?..."
> 
> Thanks
> Nikki
> 
> 
> 
> --On Friday, October 01, 2004 11:57:06 +0100 "Miles, AJ (Alistair) " 
> <A.J.Miles@rl.ac.uk> wrote:
> 
> >
> > 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
> > person.
> >
> > However, you might reasonably say that an 'email address' 
> or 'date of
> > birth' is a property of a person.
> >
> > Al.
> >
> > ---
> > Alistair Miles
> > Research Associate
> > CCLRC - Rutherford Appleton Laboratory
> > Building R1 Room 1.60
> > Fermi Avenue
> > Chilton
> > Didcot
> > 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
> >>
> >>
> >
> 
> 
> 
> ----------------------
> NJ Rogers, Technical Researcher
> (Semantic Web Applications Developer)
> Institute for Learning and Research Technology (ILRT)
> Email:nikki.rogers@bristol.ac.uk
> Tel: +44(0)117 9287096 (Direct)
> Tel: +44(0)117 9287193 (Office)
> 
Received on Friday, 1 October 2004 12:40:57 UTC

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