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

Stuart
> Is there a reason why concept equivalences established via the skos:subjectIndicator are "good" and equivalencies established via owl:sameAs are bad?
Very good question. This issue of 
sameness-which-should-not-use-owl:sameAs is something I have kept 
nailing for quite a while, and once again recently in this forum [1].
But, curiously enough, this kind of question - which I consider the most 
important for Semantic Web scalability, is always meeting on SW lists an 
astounding silence.

I have tried several explanations:

1. The question does not make sense
2. The answer is too obvious, so people don't care to answer
3. The question is too complex, so people don't dare to answer

Neither is satisfying.
1. You'll always find some people too happy to tell you that what you 
write is non-sense.
2. You'll always find a bunch of people too happy to explain you 
something obvious, just to make sure they have understood it.
3. You'll always find too many people too happy to discuss arcane 
questions they barely understand.

So, I don't know. Something like a taboo, maybe.

That said, let me try an explanation. The notion of subjectIndicator was 
inherited from the Topic Maps community, where it has two purposes :
- Indicate to humans what a topic represents
- Enable merging of topics

Since having the same subject indicator triggers the merging of topics, 
subject indicator is aka IFP. But merging of topics in topic maps is not 
ground on the strong semantic basis of OWL same-ness. Merging of topics 
is just an aggregation of information on the same point (a co-location 
of information) without the logical consequences of owl:sameAs.
I think the introduction of skos:subjectIndicator was an attempt to 
mimic the weak semantics (if semantics at all) of topic maps. But making 
it an IFP has strong consequences which have not been completely foreseen.

There again, this story points to a current lack of expressiveness in 
the whole RDF-OWL-SKOS toolkit, forbidding to say properly : Those two 
things/concepts/resources describe the same thing, yes, but, er, well, 
not really in the sense of owl:sameAs.

Bernard

[1] http://lists.w3.org/Archives/Public/semantic-web/2006Oct/0148.html

Received on Monday, 6 November 2006 23:37:39 UTC