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Re: Proposal to resolve ISSUE-81

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Tue, 25 Mar 2008 23:43:53 -0400
Message-Id: <2841B804-BE65-4251-BEB7-C8B64990581C@gmail.com>
Cc: "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
To: Michael Schneider <schneid@fzi.de>

Based on your comment and some other conversation, perhaps a better  
choice is

EquivalentClasses(ObjectIntersectionOf(ObjectOneOf(John)  
ObjectHasValue(hasMother  Mary)) owl:Nothing )

This has a better parallel for NegativeDataPropertyAssertion, in that  
it can be valid OWL 1.0 DL. (no complement of oneOf(literal) in OWL 1.0)

-Alan

On Mar 24, 2008, at 8:01 AM, Michael Schneider wrote:

> Hi, Alan!
>
>> -----Original Message-----
>> From: public-owl-wg-request@w3.org
>> [mailto:public-owl-wg-request@w3.org] On Behalf Of Alan Ruttenberg
>> Sent: Sunday, March 23, 2008 3:48 PM
>> To: Web Ontology Language ((OWL)) Working Group WG
>> Subject: Proposal to resolve ISSUE-81
>>
>>
>> To resolve this issue I propose that NegativeObjectPropertyAssertion
>> be transformed into the equivalent class assertion. In order to
>> support tools that wish to preserve the presentation of this axiom as
>> NegativeObjectPropertyAssertion we use the axiom annotation mechanism
>> with a new annotation property: syntaxHint.  syntaxHint would be
>> considered optional - not all tools need serialize using it, nor all
>> tool pay attention to it.
>>
>> So
>> NegativeObjectPropertyAssertion(hasMother John Mary)
>>
>> Is translated in to
>>
>> ClassAssertion(
>>   Annotation(syntaxHint NegativeObjectPropertyAssertion)
>>   John ObjectAllValuesFrom(hasMother ObjectComplementOf(ObjectOneOf
>> (Mary))))
>
> I will only talk here about having this as an RDF syntax for  
> negative property assertions. I won't talk about the functional  
> syntax.
>
> I would not totally object to your proposal, but let me say that I  
> have a personal preference for a more direct encoding.
>
> Aside from the round-tripping issue (ignoring your "syntaxHint"  
> annotation for the moment :-)), I can also see a slight semantic  
> issue with the above encoding, in particular for /data/ property  
> assertions. I feel that the following idea might be worth to be  
> considered: Statements of the form
>
>   NegativeDataPropertyAssertion(dp s o)
>
> should be allowed, where 'dp' denotes a data property, and 'o'  
> denotes an individual(!) instead of a datavalue. The reason is that  
> I just want to state that the triple "s p o" does *not* exist, and  
> for an 'o', which does *not* denote a datavalue, this is, of  
> course, always a true assertion.
>
> This is probably a controversial idea. Whatever one's opinion is  
> here, the approach given by the above encoding will *not* support  
> this idea:
>
>   * In Full, the object o will be coerced into a datavalue, which  
> may lead to undesired semantical side effects in certain situations.
>
>   * In DL, if 'o' is an individual, then this will produce an  
> error, AFAICS. [FIXME: There is no individual/datavalue punning in  
> 1.1-DL, since URIs cannot denote datavalues?]
>
> These effects can at least be technically avoided with a direct  
> encoding such as the current one based on reification. One can, of  
> course, opt to introduce these effects explictly in such a direct  
> encoding. Anyway, one has then the /option/ to do so. So what my  
> idea at least shows is that the above encoding of negative property  
> assertions carries perhaps a bit more information than necessary.
>
> But again, as for ISSUE-67, I prefer to avoid RDF reification  
> (again for political reasons in the first place), and would instead  
> opt to introduce a dedicated feature specific vocabulary:
>
>   _:x rdf:type owl11:NegativeObjectPropertyAssertion
>   _:x owl11:propertyAssertionSubject s
>   _:x owl11:propertyAssertionPredicate p
>   _:x owl11:propertyAssertionObject o
>
> And analog for 'owl11:NegativeDataPropertyAssertion' (I won't argue  
> about names, though).
>
>> -Alan
>>
>> meta: ISSUE-103
>
> 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@fzi.de
> Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555
>
> FZI Forschungszentrum Informatik an der Universität Karlsruhe
> Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
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Received on Wednesday, 26 March 2008 03:55:57 GMT

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