RE: [SKOS] ISSUE-83 semantics of scheme containment properties

If this can help, I think that
> ex:cs skos:hasTopConcept ex:c.
> entails
> ex:c skos:inScheme ex:cs
is enough... because technically we do not gain any new information by
entering a new property such "skos:topConceptInScheme "... We can just
extract all topConcept with a query.
 
hope this helps
Margherita

	-----Original Message----- 
	From: public-swd-wg-request@w3.org on behalf of Antoine Isaac 
	Sent: Sat 7/26/2008 00:44 
	To: Alistair Miles 
	Cc: public-swd-wg@w3.org 
	Subject: Re: [SKOS] ISSUE-83 semantics of scheme containment
properties
	
	


	Hi Alistair,
	
	I agree that the first solution you propose makes the trick from a
	semantic perspective. But I don't like having an extra vocabulary
	element just for this...
	
	I had actually written [1] to look a bit like the general entailments
of
	the SKOS Reference, thinking that we could  just have:
	> ex:cs skos:hasTopConcept ex:c.
	> entails
	> ex:c skos:inScheme ex:cs
	>  
	
	Otherwise I think you can indeed introduce a non-named property in an
	OWL axiom, like (hoping I'm not making any mistake...)
	
	skos:hasTopconcept rdfs:subPropertyOf [ a owl:ObjectProperty;
	owl:inverseOf skos:inScheme .] .
	
	Again, I would definitively favor one of these two options over
	introducing a new property.
	
	Cheers,
	
	Antoine
	
	[1]
http://lists.w3.org/Archives/Public/public-swd-wg/2008May/0068.html
	
	
	> Hi Antoine,
	>
	> I'm just trying to figure out how to implement the resolution [1]
to
	> issue 83 [2] in the SKOS reference.
	>
	> The most obvious way is to introduce a new property, called
something
	> like skos:topConceptInScheme, and introduce two new statements into
the
	> SKOS data model, that skos:topConceptInScheme is a sub-property of
	> skos:inScheme, and that skos:topConceptInScheme is the inverse of
	> skos:hasTopConcept.
	>
	> Another way would be to avoid introducing any new properties, and
to
	> include a new statement in the data model, something like, "the
inverse
	> of skos:hasTopConcept is a sub-property of skos:inScheme", or "if a
	> scheme has a top concept, then the top concept is in that scheme",
	> or ... ?
	>
	> At the moment I favour the first approach. It has an obvious
meaning in
	> terms of RDFS/OWL. The second approach has no obvious translation
in
	> RDFS/OWL, and is difficult to word.
	>
	> What do you think?
	>
	> Cheers,
	>
	> Al.
	>
	> [1]
http://lists.w3.org/Archives/Public/public-swd-wg/2008May/0068.html
	> [2] http://www.w3.org/2006/07/SWD/track/issues/83
	>
	>