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Re: subgraph/entailment

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Wed, 7 Sep 2005 09:27:34 -0400
Message-Id: <88598f58264e1844524d91ab5aeef491@isr.umd.edu>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: Dan Connolly <connolly@w3.org>

On Sep 7, 2005, at 9:19 AM, Dan Connolly wrote:

> On Tue, 2005-09-06 at 23:35 -0400, Bijan Parsia wrote:
>> On Sep 6, 2005, at 10:35 PM, Dan Connolly wrote:
>>
>>> On Wed, 2005-09-07 at 03:47 +0200, Enrico Franconi wrote:
>>> [...]
>>>> Now we have three possibilities:
>>>
>>> I'm getting lost.
>>
>> To pick up the dialectic as I understand it, Enrico thought (as many 
>> do
>> on first reading) that the subgraph language *precluded* extending
>> SPARQL to query datasets expressed in more expressive logics than
>> RDF/RDFS (while respecting the semantics of those logics).
>
> Yes, as designed, it does. The way more expressive logics fit into
> this design is that they contribute to the graph that's being
> queried against...

[snip]
>> Er...so SPARQL is defined only for RDF graphs without their semantics?
>> Or, rather, only against the *asserted* triples in an RDF graph?
>
> Yes.
[snip]

This is a contradiction (I think we have a terminology conflict). The 
contribution of more expressive logics cannot be asserted triples. By 
"asserted" I meant, "asserted in the original document/dataset" not 
"asserted 'by inference'".

If the way around this is to do some sort of closure and then "dump" 
the data (roughly) and reload it..well....now we're requiring 
extrasilly gyrations to kill clarity and avoid some important details.

Cheers,
Bijan.
Received on Wednesday, 7 September 2005 13:27:39 GMT

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