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Re: Editorial thread for BGP matching

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 25 Jan 2006 13:37:14 -0600
Message-Id: <p06230906bffd7e1c68fc@[]>
To: Enrico Franconi <franconi@inf.unibz.it>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>

>On 25 Jan 2006, at 18:58, Enrico Franconi wrote:
>>On 25 Jan 2006, at 18:55, Enrico Franconi wrote:
>>>On 25 Jan 2006, at 18:41, Seaborne, Andy wrote:
>>>>Enrico Franconi wrote:
>>>>>Another proposed simplification:
>>>>>Definition:  Scoping Set
>>>>>A Scoping Set B is a set of RDF terms formed by the combination of:
>>>>>      * all URIs
>>>>>      * blank node names
>>>>>This could just be:
>>>>>A Scoping Set is an arbitrary subset of the RDF terms.
>>>>I thought the point was that it is always all IRIs (oops 
>>>>s/URI/IRI) and some set of blank nodes (but not all of them). 
>>>>That then ties to "The identifiers introduced by S all occur in 
>>>>B." in the BGP matching defn.
>>>Well, yes, you are right.
>>More precisely: in sparql we have all the B includes only the 
>>bnodes in G'; then, we have to leave room for future extensions. 
>>For example, for OWL data queries, B does not include any bnode; 
>>and there is an understanding of RDF entailment where you may want 
>>to have all bnodes in B.
>OK, I have to read what I write :-)
>s/all the B/that B/

It must be more nuanced than this for the general case. I don't think 
we can stipulate that B must contain *all* IRIs, in general. For 
example, OWL-DL would want to restrict the IRIs allowed in answer 
bindings to exclude the excluded vocabulary. (?Enrico?) Also, someone 
might offer a specialized query service that focused on giving 
particular classes of answer and ignores others, for example. I think 
if we use B then we should just keep it as general as possible in the 
general case, and require future specs to specify it appropriately in 
each case.


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Received on Wednesday, 25 January 2006 19:37:24 UTC

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