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Re: Use cases wrt Dataset proposal (UC 1.5, UC 5.2)

From: Dan Brickley <danbri@danbri.org>
Date: Thu, 1 Mar 2012 08:48:47 +0100
Message-ID: <CAFfrAFppPhoik9_7cMqg2gvoGu4hWzOvUwXmb5nO_f=wjO8Uaw@mail.gmail.com>
To: Antoine Zimmermann <antoine.zimmermann@emse.fr>
Cc: Pat Hayes <phayes@ihmc.us>, RDF WG <public-rdf-wg@w3.org>
On Wednesday, 29 February 2012, Antoine Zimmermann wrote:

>
>
> Le 29/02/2012 16:27, Pat Hayes a écrit :
>
>>
>> On Feb 29, 2012, at 8:43 AM, Antoine Zimmermann wrote:
>>
>>  *Beware*: this is about design solutions using the dataset proposal
>>> as a whole. It is not strictly related to the semantics. It
>>> explains concretely how one could store things in a dataset,
>>> possibly entail new things according the dataset semantics of [2]
>>> and so on, such that eventually it addresses the use case. So it
>>> contains a number of things that applications should do to address
>>> the UCs, independently of the truth values of triples or "named"
>>> graphs.
>>>
>>>
>>> UC 1.5: Exchanging the contents of RDF stores
>>>
>>> This is trivial. RDF stores mostly implement SPARQL datasets, so it
>>> suffices to have a serialisation syntax for datasets. It does not
>>> matter what the semantics is. TriG or N-Qauds will do.
>>>
>>>
>>> UC 5.2: OWL's “Ontology Documents”
>>>
>>> Currently, OWL imports statement means that an OWL processor should
>>> fetch wathever document it founds when "accessing" the imported URI
>>> (using whatever protocol it needs, see [1]). This behaviour is
>>> independent of the formal semantics of OWL ontologies. It's an
>>> operation that must be done prior to any interpretation of the
>>> ontology.
>>>
>>> If multiple ontologies are stored in a dataset, it seems reasonable
>>> to use the import mechanism offline, where instead of a HTTP
>>> lookup, the system directly fetches from the corresponding "named"
>>> graph.
>>>
>>
>> Whoa. I dont think this is at all reasonable. This changes the
>> meaning of owl:imports, in effect (or extends it in a new way). After
>> all, the URIs used as labels in a datastore might *refer* to
>> anything, and in particular, they might refer to a different ontology
>> stored somewhere on the web identified by an http URI. So the meaning
>> of an imports might change when the ontology containing it is put
>> into a dataset and taken offline.
>>
>
> owl:imports is a strange beast, and the OWL specs allows things with this
> predicate that you are possibly not imagining. It truly is what I say: you
> take the URI (as a syntactic element), you apply whatever protocole you
> want to apply to GET something, and what you get is considered to be an
> ontology document that you have to parse.
>
> If I say in an ontology document:
>
> <>  owl:imports  <http://zimmer.**aprilfoolsreview.com/antoine#**me<http://zimmer.aprilfoolsreview.com/antoine#me>>
> .
>
> then, what I get, according to the OWL specs, is an ontology with the
> content of http://zimmer.**aprilfoolsreview.com/antoine<http://zimmer.aprilfoolsreview.com/antoine>included, in spite of <
> http://zimmer.**aprilfoolsreview.com/antoine#**me<http://zimmer.aprilfoolsreview.com/antoine#me>>
> denoting a foaf:Person.
>
> Please take a look at the OWL 2 spec section 3.2 to check.
>
>
Why should an ontology's RDF description not include information about
real-world entities?

Dan


>
>
>
>> At the very least, if we mandate this, then we need to clarify the
>> semantic role of "label" URIs in datasets.
>>
>> Pat
>>
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>>
>>
>>
>>
>>
>>
>>
> --
> Antoine Zimmermann
> ISCOD / LSTI - Institut Henri Fayol
> École Nationale Supérieure des Mines de Saint-Étienne
> 158 cours Fauriel
> 42023 Saint-Étienne Cedex 2
> France
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>
>
Received on Thursday, 1 March 2012 07:49:21 GMT

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