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skos:Concept and "real world things"

From: François-Paul Servant <francois-paul.servant@renault.com>
Date: Tue, 13 May 2008 15:19:09 +0200
Message-ID: <4829954D.9050707@renault.com>
To: public-esw-thes@w3.org
CC: fps <fps@semanlink.net>


In the "Linked Data" community, people give URIs to "real world things", such as 
animals, cities or persons.

In SKOS, we define and give URIs to concepts, "ideas or meanings that are unit 
of thoughts..."

It seems obvious that there is a deep (and possibly complex relation) between 
skos:Concept(s) and "real world (physical) things" (I would even say that, 
except maybe in very particular domains such as mathematics, there is no way to 
define a concept without relating it to "real world things").

For instance, there is a relation between the skos:Concept "ex:platypus" 
declared in a given SKOS scheme and the funny australian animal which was given 
the URI "dbPedia:Platypus" by the dbPedia project:

skosex:platypus p dbPedia:Platypus

What kind of property  should be used for "p" in that statement?

We can think of:
1) owl:sameAs
2) skos:exactMatch
3) moat:meaningURI
4) dc:subject
5) ...

1) doesn't seem OK (for reasons that include the reasons why we do not use 
owl:sameAs to state that 2 skos:Concepts are the same)

2) implies that dbPedia:Platypus is a skos:Concept. DBPedia doesn't state that, 
and it is controversial to say that a real world thing is a conceptual resource. 
SKOS doesn't seem to want to allow such statements: in the wiki [1] we can read:
"So, for a resource of type skos:Concept, any properties of that resource (such 
as creator, date of modification, source etc.) should be interpreted as 
properties of a concept, and not as properties of some 'real world thing' that 
that resource may be a conceptualisation of."

3) MOAT ("Meaning Of A Tag" [2]) relates tags to their meaning. The meaning of a 
tag is an instance of a class "Meaning" (that probably could be considered as a 
skos:Concept). A dedicated property moat:meaningURI is used to link the 
"Meaning" to a "real world thing". We have something like this:

tag:platypus moat:hasMeaning moat:meaning_platypus
moat:meaning_platypus moat:meaningURI dbPedia:Platypus

4) seems weak

5) any better idea ?

The pattern used in [3] (MOAT) seems OK to me: we have on one side the 
"Concept", and on the other the "real world thing". This allows to write 
statements about the two entities, which are indeed distinct, and at the same 
time allows to clearly define a concept, when existing URI of a real world thing 
already exists.
However, I would'nt feel bad with solution 2 (I am ready to consider real world 
things as concepts). But of course, my preference is 5 ;-)

Anyway, shouldn't SKOS define a property allowing to state the relation between 
a skos:Concept and the real world thing that that skos:Concept is the 
conceptualisation of?

Best Regards,

François-Paul Servant

[1] http://www.w3.org/2006/07/SWD/wiki/SkosDesign/ConceptSemantics
[2] http://moat-project.org/
Received on Tuesday, 13 May 2008 13:21:05 UTC

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