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Re: comments on RDF mapping

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Fri, 26 Oct 2007 09:38:32 -0700
Message-Id: <2903CE1D-55F4-45B3-BBD0-8244BF4C3DC0@gmail.com>
Cc: Boris Motik <boris.motik@comlab.ox.ac.uk>, public-owl-wg@w3.org
To: Jeremy Carroll <jjc@hpl.hp.com>

Hi Jeremy,

My understanding is that the intention is not to provide a way to get  
around the univocity of a URI. Rather, some aspects of making that  
work are not currently known to be decidable, so a compromise is  
offered  insofar as some entailments that would be theoretically  
desired are skipped, in order to make progress towards a shared goal.

I wonder whether we can make some fixes to address cases such as the  
one you point out, particularly when there is no impact on  
decidability. So perhaps we could consider, in this case, abandoning  
the distinction between subObjectPropertyOf and subDataPropertyOf so  
that a subProperty assertion applies to both kinds.

There will still be an issue with property chains. But I wonder what  
you think about the general strategy: Making it clear in the  
documentation that we discourage use of punning to get around  
univocity, that current behavior that allows this may disappear in  
future versions of OWL, and patching, to the extent that is feasible  
without new theoretical work, the current spec in the way that I  
suggest above.

As a meta point, could we stay away from statements of the sort :  
"i.e. punning is an unhelpful idea."? I don't think it is helpful, as  
there are clearly situations where other people do think it is  
helpful. Let's instead focus on making things work as best we can.

-Alan


On Oct 26, 2007, at 8:42 AM, Jeremy Carroll wrote:

>
>
>
> Boris Motik wrote:
>> Hello,
>> I would just like to point out that, with or without punning,  
>> already in OWL 1.0 you have an ontology O containing the triples
>> (1)--(5). Hence, the problem that I described in my previous e- 
>> mail is already there and is not specific to OWL 1.1.
>
> Not correct.
>
> In OWL 1.0 DL, the triples (1) - (5) is a syntax error.
> Hence, in OWL 1.0, the ontology is OWL Full.
> The subPropertyOf triple (5) is well-defined, by the RDF Semantics.
> Triples (1), (2), (3) and (4) are all logical consequences of (5)  
> and the OWL Full semantics. So there is no problem in OWL 1.0.
>
> All the problems that OWL 1.1 are trying to solve with these five  
> triples arise from OWL 1.1
>
> Jeremy
>
>
>> Regards,
>> 	Boris
>>> -----Original Message-----
>>> From: public-owl-wg-request@w3.org [mailto:public-owl-wg- 
>>> request@w3.org] On Behalf Of Jeremy Carroll
>>> Sent: 24 October 2007 17:23
>>> To: public-owl-wg@w3.org
>>> Subject: Re: comments on RDF mapping
>>>
>>>
>>>
>>> Boris
>>> [[
>>> Imagine that your ontology O contains all the following triples:
>>>
>>> (1)  <X rdf:type owl:ObjectProperty>
>>> (2)  <X rdf:type owl:DataProperty>
>>>
>>> (3)  <Y rdf:type owl:ObjectProperty>
>>> (4)  <Y rdf:type owl:DataProperty>
>>>
>>> (5)  <X rdfs:subPropertyOf Y>
>>>
>>> Note that triples (1) and (2), and (3) and (4) are allowed  
>>> because you
>>> can have punning in OWL 1.1; hence, you can use the same name
>>> as both object and a data property.
>>>
>>> If you now try to produce an axiom that corresponds to triple  
>>> (5), you
>>> have a problem: is this axiom representing inclusions between
>>> the object property X and the object property Y, or between the data
>>> property X and the data property Y?
>>> ]]
>>>
>>> i.e. punning is an unhelpful idea.
>>>
>>> The OWL Full treatment of a URI used as both a DataProperty and an
>>> ObjectProperty is that it represents a single property.
>>>
>>> This treatment is in OWL 1.0 Full, and extensively deployed (for  
>>> example
>>> in the RDF subset of OWL).
>>>
>>> Jeremy
>>>
>
>
Received on Friday, 26 October 2007 16:38:53 GMT

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