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Re: Final text for Basic Graph Patterns

From: Enrico Franconi <franconi@inf.unibz.it>
Date: Fri, 20 Jan 2006 07:43:06 +0100
Message-Id: <97D69D9A-25F0-49DD-A2CB-BB1F56B86AFA@inf.unibz.it>
Cc: Dan Connolly <connolly@w3.org>, Pat Hayes <phayes@ihmc.us>, RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: Bijan Parsia <bparsia@isr.umd.edu>

On 20 Jan 2006, at 07:17, Bijan Parsia wrote:
>> What I am also saying that you have to transport the syntactic  
>> constraints that OWL-DL expressions have, to similar syntactic  
>> constraints to SPARQL queries when using OWL-DL entailment.  
>> Namely, in queries bnodes and variables are not in property  
>> position of any triple, nor in object position of rdf:type  
>> triples, and there is no rdf, rdfs, owl vocabulary symbol in the  
>> query with the exception of rdf:type in property position.
> [snip]
> For the record, I always presumed that for OWL  DL Entailment,  
> you'd work with the abstract syntax, as that's how entailment is  
> defined:
> 	http://www.w3.org/TR/owl-semantics/direct.html#3.4
> So, if I were going to write the spec for SPARQL parameterized   
> with OWL DL entailment, I would first define the abstract syntax of  
> the basic query in terms of the abstract syntax (which would only  
> allow query variables in certain places), then a transformation to  
> triples of that abstract syntax.
> So I don't think it's that big of a stretch, actually. You *could*  
> define a query syntax with variables in funky places, but it's not  
> immediate. And it's not immediate from the SPARQL (it's not *far*,  
> cause you can sorta see where some variables "would go" if you  
> tried to apply the reverse transformation to triples to sparql GPs).

Fair enough.
Received on Friday, 20 January 2006 06:43:19 UTC

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