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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 13:44:34 +0100
Message-ID: <350DC7048372D31197F200902773DF4C05E50C5A@exchange11.rl.ac.uk>
To: "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>

Who's impressed I got the word 'metaphysical' into that last email?  Didn't
do a degree in Zoology for nothing you know.

Btw for non-RDF folks, an RDF 'resource' is a 'thing' basically.

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 Miles, AJ 
> (Alistair)
> 
> Sent: 01 October 2004 13:41
> To: 'public-esw-thes@w3.org'
> Subject: FW: [Proposal][SKOS-Core] skos:denotes
> 
> 
> 
> 
> 
> 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 12:45:06 UTC

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