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Re: subgraph/entailment

From: Enrico Franconi <franconi@inf.unibz.it>
Date: Thu, 8 Sep 2005 12:55:46 +0200
Message-Id: <4E9D60B9-95B1-4AEC-9CB5-A0E33BA60CCA@inf.unibz.it>
Cc: jos.deroo@agfa.com, bparsia@isr.umd.edu, connolly@w3.org, public-rdf-dawg@w3.org, public-rdf-dawg-request@w3.org
To: andy.seaborne@hp.com

On 8 Sep 2005, at 10:37, Seaborne, Andy wrote:
> For SPARQL to be useable, it must be possible to make queries  
> against the exact triples in the base data.  Other modes shoudl  
> also be possible determined by what service/graph/repository is  
> being queried.
>
> It must be possible to access the base data for SPARQL to be  
> useable for any application that is involved in building a graph  
> while at the same time accessing it.  I coined the term "zero- 
> entailment" as I couldn't find extsing terminology.
>
> I understand this to be part of the "Local Query" requirement. I  
> had in mind that the query language be usable in applications that  
> require access to the base data so they can add new triples, and  
> they themselves deliver inference services to other applications.

The point I am raising is in the case you want to be compliant with  
RDF MT, which seems to me necessary for SPARQL: we don't want SPARQL  
to be unable to correctly answer queries under the official standard  
RDF-MT semantics. The RDF-MT semantics introduces two entailments:  
the simple one, where basically the graph is un-altered, and  
therefore it corresponds to what above you refer to as "exact  
triples" or "zero entailment". Then, there is the RDF-entailment. If  
you take seriously the official standard RDF-entailment as defined in  
the official standard RDF-MT semantics, I say that you have to have  
the behaviour that Bijan and me were arguing about.

cheers
--e.
Received on Thursday, 8 September 2005 10:56:20 GMT

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