RE: Astounding silence about same-ness Re: Concept Equivalence, IFPs, skos:subjectIndicator and owl:sameAs

Bernard,

> Hello Stuart
> 
<snip/>

> Some precisions to mail it.
> > Ok... so the relationship between a topic and a subject indicator is

> > functional.
> >   
> I guess you mean "inverse functional" here.

Actually... I had meant functional, because I thought from the earlier
exchange around may 'bogus' example, that a skos:Concept could have only
on skos:subjectIndicator. However, given what you go onto say below, the
expectation is such that if there are multiple subject indicators that
are all indicators of the same (whole) subject (as opposed to
constituents of some aggregate subject that I had contrived in my
example).

> - A topic can have more than one subject indicator
> - Two topics which have at least one subject indicator in 
> common are representing the same subject (and should be 
> merged in a fully processed topic map)

Ok...

> The relation between topic and *subject* is functional : a 
> topic represents a single subject.
> Which means when a topic has more than one subject 
> indicators, they all indicate the same subject

Ok... so, the relationship between a topic and a subject is functional
and:  1) direct in the case where the subject is a directly web
accessible resource; 2) indirect via a subject indicator which has an
inverse functional relation with the subject, in the case where the
subject is not a directly accessible web resource. FWIW subjects that
are web accessible resources could also be indicated indirectly.

If that is correct, then a 'problem' with skos:subjectIndicator is that
as it is currently framed is that it relates a skos:Concept (a tm:Topic
like thing as you seem to concur below) directly to a subject indicator
without an intervening tm:Subject. The subject could be induced from a
different inverse functional relation between subject and subject
indicator... but as currently defined the inverse functional relation is
between skos:Concept and subject indicators... which I think we (you and
I) agree is wrong.

> > That makes the example I tried to contrive very bogus.
> >   
> Indeed, but useful for clarification.
> > So... in topic map terms... is a skos:Concept also a tm:Topic. I
think 
> > the answer is probaly yes.
> >   
> More or less. See a very good introduction to RDF vs TM by 
> Lars Marius Garshol, who is certainly the one to have gone 
> deep in the details of this.
> http://www.ontopia.net/topicmaps/materials/tmrdf.html

Thanks. I will take a look.

> > An appropriate subject indicator (as you say) would be a (single?) 
> > document that describes the subect in clear an unambiguous terms.
> >
> > I question the single, because there could be multiple unambiguous 
> > accounts of given subject and reaching common agreement that one was

> > in some sense primary over the others would be 'tricky'.
> You're right. There is no technical way to prevent people to 
> mint different subject indicators for the same subject. 
> Either they are not aware there is already one available, or 
> they don't trust it, or they prefer to have one in their own 
> namespace, whatever. Same problem as people minting different 
> URIs for the same concept, actually.
> > It's almost as if the subject indicator ought to be an intervening
(possibly 
> > blank) node off of which multiple accounts could be 'hung'.
> >   
> Absolutely. This is the second level of indirection we have 
> been discussing with Mark. And actually in the introduction 
> to Published Subjects in XML Topic Maps book, I was already 
> suggesting that a subject indicator could be a kind of empty 
> hub, taking its meaning from resources linked through it.

Hmmm.... if they were all like that, it doesn't sound like there would
be much available in the way of human consumable clear, unambiguous
subject descriptions.

<snip/>

> Bernard

Thanks again,

Stuart
--

Received on Wednesday, 8 November 2006 14:39:05 UTC