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

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 29 Feb 2012 09:27:24 -0600
Cc: RDF WG <public-rdf-wg@w3.org>
Message-Id: <1D677B21-C15A-4F95-8AA5-79906A1FC21B@ihmc.us>
To: Antoine Zimmermann <antoine.zimmermann@emse.fr>

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. 

At the very least, if we mandate this, then we need to clarify the semantic role of "label" URIs in datasets.


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Received on Wednesday, 29 February 2012 15:28:03 UTC

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