- From: Pierre-Antoine Champin <swlists-040405@champin.net>
- Date: Thu, 04 Dec 2008 13:16:17 +0000
- To: Bijan Parsia <bparsia@cs.man.ac.uk>
- CC: Owl Dev <public-owl-dev@w3.org>, Michael Schneider <schneid@fzi.de>
Bijan Parsia wrote:
> I have no will power.
>
> I hate myself.
:-D thanks anyway for digging faster than me in the document.
As a matter of fact, I realized with Michael's and your mail that what I
*really* wanted to write was:
_:x rdf:type owl:NegativePropertyAssertion (1)
_:x owl:sourceIndividual _:x (2)
_:x owl:assertionProperty rdf:type (3)
_:x owl:targetIndividual owl:NegativePropertyAssertion (4)
However, reading the section you kindly pointed to, it seems to me that
there is no paradox either.
Indeed, the belonging of I(_:x) to IEXT(owl:NegativePropertyAssertion)
seems to be *completely irrelevant* to the interpretation of triples
(2-4). So triple (1) says one thing, triples (2-4) say another thing...
this is a plain old contradiction.
Cool. :-)
pa
>
> On 4 Dec 2008, at 11:11, Pierre-Antoine Champin wrote:
> [snip]
>> Wouldn't
>>
>> _:x rdf:type owl:NegativePropertyAssertion
>> _:x owl:sourceIndividual _:x
>> _:x owl:assertionProperty owl:sourceIndividual
>> _:x owl:targetIndividual _:x
>>
>> a perfect example of that paradox (in OWL Full, of course) ?
>>
>> What am I missing?
>
> Semantic conditions for negative property assertions are given by table
> 5.15:
> <http://www.w3.org/2007/OWL/wiki/RDF-Based_Semantics#tab-semcond-negativeassertions>
>
>
> (Pretend the triples are numbered 1-4)
>
> So, (and I'm just going to use "x"). Let's try the following
> interpretatioN"
>
> D = {x, sI, aP, tI, NPA,type}
>
> IEXT(NPA) = {x}
> IEXT(sI) = {<x,x>}
> IEXT(aP) = {<x, sI>}
> IEXT(tI) ={<x, x>}
> IEXT(type) = {<x, NPA>}
>
> Now, looking at the conditions:
> 〈x,u〉 ∈ IEXT(I(owl:sourceIndividual)),
> 〈x,p〉 ∈ IEXT(I(owl:assertionProperty)),
> 〈x,w〉 ∈ IEXT(I(owl:targetIndividual))
>
> u = x
> p = sI
> w = x
> From this it follows from the condition:
> 〈u,w〉 not in IEXT(sI)
> that
> <x, x> not in IEXT(sI)
> which is false. Thus the assertion is false.
>
> Not seeing any paradox. Just a contradiction like C&~C.
>
> Cheers,
> Bijan.
>
Received on Thursday, 4 December 2008 13:16:59 UTC