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Re: [Fwd: Comments on SPARQL] (entailment, soundness, completeness)

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Tue, 20 Sep 2005 08:55:56 -0400
Message-Id: <365a278ddd0afa33c527e25573ac3acf@isr.umd.edu>
Cc: Enrico Franconi <franconi@inf.unibz.it>, Pat Hayes <phayes@ihmc.us>, RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: Dan Connolly <connolly@w3.org>

On Sep 20, 2005, at 7:04 AM, Dan Connolly wrote:
[snip]
> Enrico, elsewhere in your message about "Adoption of entailment in 
> SPARQL"
> of September 19, 2005 11:55:09 PM GMT+01:00, you wrote "here we don't
> argue whether this is useful and how this is going to be used." Note 
> that I
> pretty much stopped reading at that point.

I think you were mislead by Enrico's words there. There are plenty of 
places in that note that he appeals to existing, documented SPARQL use 
cases to motivate his technical points, e.g.,

"""ON REDUNDANCY OF TOLD BNODES IN ANSWERS
[issue <http://www.w3.org/2001/sw/DataAccess/issues#rdfSemantics>]

"""
Should queries of non-lean and lean graphs that entail each other
give the same answers?
"""

The answer to this question should be *yes*. See use case 1,
"Publishing on the Web", in
<http://lists.w3.org/Archives/Public/public-rdf-dawg/2005JulSep/0430>).
This is also relevant, as noted by PFPS, to enable interoperability
between different interoperating implementations of RDF."""

> I'll be more motivated to study the technical
> details when I know which user requirements, use cases, and 
> applications
> a proposal is intended to address and which it's not intended to 
> address.\
[snip]
Since the two major alternative approaches as I understand them 
"virtual graphs" vs. entailment bases are, at least in some forms, 
*equivalent* (I'm not clear pat means them to be anymore!) then the 
whole first section of that email is motivate by spec clarity issues. 
So, the use case *from my perspective* is producing interoperable 
implementations for a variety of semantics imposed on the source 
documents. For example, I may want to query the syntax of an RDF 
document (i.e., with full asserted redundancy) for an editor 
applicaiton, or I may want just the non-redundant information in the 
graph (e.g., I don't want to have to post query filter out that someone 
loving someone since mary loving john was already in there).

Cheers,
Bijan.
Received on Tuesday, 20 September 2005 12:56:38 GMT

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