[Pellet-users] FunctionalObjectProperty: No owl:sameAs triples on query

[Michael Schneider]

>-----Original Message-----
>From: Evren Sirin [mailto:evren at clarkparsia.com] 
>Sent: Tuesday, October 02, 2007 9:53 PM
>To: Michael Schneider
>Cc: pellet-users at lists.owldl.com
>Subject: Re: [Pellet-users] FunctionalObjectProperty: No 
>owl:sameAs triples on query
>
>This is the known limitation regarding owl:sameAs (similarly for 
>owl:differentFrom) property as documented in BUGS.txt. The description 
>there is a little misleading (suggesting you only miss sameAs triples 
>when the predicate is variable) because as you realized it happens in 
>other cases too.  The workaround is to make one of the subject 
>or object 
>ground, e.g. listStatements(alice, OWL.sameAs, null) or 
>listStatements(null, OWL.sameAs, alice), which should return all 
>equivalents (including the resource itself).
>
>Cheers,
>Evren

I see! Thanks, Evren, for the clarification!

Cheers,
Michael

>
>On 10/1/07 3:12 PM, Michael Schneider wrote:
>> Hi!
>>
>> Probably yet another "testcase" of the Pellet/Jena interface 
>issue. Well,
>> the more of them, the easier to identify the problem, and 
>the better to see
>> the extend of the problem. :-)
>>
>> This time I have a FunctionalObjectProperty 'fp', together with three
>> instances (of owl:Thing) 'alice', 'bob' and 'charly', and 
>the two triples:
>>
>>     * alice fp bob
>>     * alice fp charly
>>
>> Of course, from this, the triple
>>
>>     bob owl:sameAs charly
>>
>> should be inferrable. But when doing a query over the 
>inferences (either via
>> Topbraid Composer, or with the Pellet commandline tool, or 
>programmatically
>> with Jena's 'listStatement()' method), I do not get this 
>triple. But I get
>> it, if I directly ask for its existence with Jena's 
>'Model.contains()'
>> method.
>>
>> See below for the example ontology and some Jena/Pellet code, which
>> demonstrates the problem. The interesting part is that for the
>> 'listStatement' iteration, I called it with the parameters
>>
>>     (null, OWL.sameAs, null)
>>
>> but even then it did not return the expected result.
>>
>> Cheers,
>> Michael
>>

--
Dipl.-Inform. Michael Schneider
FZI Forschungszentrum Informatik Karlsruhe
Abtl. Information Process Engineering (IPE)
Tel  : +49-721-9654-726
Fax  : +49-721-9654-727
Email: Michael.Schneider at fzi.de
Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555

FZI Forschungszentrum Informatik an der Universität Karlsruhe
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