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Re: Subgraph results counter-example(s)

From: Eric Prud'hommeaux <eric@w3.org>
Date: Sat, 12 Jun 2004 08:12:17 +0900
To: Dan Connolly <connolly@w3.org>
Cc: Andy Seaborne <andy.seaborne@hp.com>, Rob Shearer <Rob.Shearer@networkinference.com>, RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-ID: <20040611231217.GE15900@w3.org>

On Fri, Jun 11, 2004 at 01:29:55PM -0500, Dan Connolly wrote:
> 
> On Fri, 2004-06-11 at 01:29, Eric Prud'hommeaux wrote:
> [...]
> > If the data in the KB can be written in RDF and we ask
> > 
> > Q: who is friends with either Eddie or Jane?
> > KB: Bob is friends with Eddie.
> >     Sue is friends with Eddie or Jane.
> > 
> > the the KB can say, in whatever ontology is appropriate:
> > 
> > A: Bob		Bob friendsWith Eddie.
> >    Sue		Sue friendsWith disjunctionA.
> > 		disjunctionA leftSide Eddie.
> > 		disjunctionA rightSide Jane.
> 
> Er... let's please don't do that... that only works if
> the friendsWith property knows about leftSide/rightSide.

True, I should have spelled it friendList. Which underscores the
point that we don't have a way to say friendsWith A or B.

> I've seen RDF data files that assume that
> 	<book> dc:creator [ a rdf:Bag; rdf:_1 :Eric; rdf:_2 :Dan ].
> means the same thing as
> 	<book> dc:creator :Eric.
> 	<book> dc:creator :Dan.
> but the definition of dc:creator says nothing of the sort.
> (I think; if it does, pick a property that doesn't.)
> 
> > If the data can't be expressed in RDF, isn't that out of scope? chair?
> 
> Well, yes, that's what the charter says, as you pointed out...
> 
> > http://www.w3.org/2003/12/swa/dawg-charter#scope
> > [[
> > The principal task of the RDF Data Access Working Group is to gather
> > requirements and to define an HTTP and/or SOAP-based protocol for
> > selecting instances of subgraphs from an RDF graph.
> > ]]
> 
> but presumably the charter says that for good reasons that
> (1) motivated the charter writers to put it there
> (2) gained support of the AC
> (3) gained support of those of us who reviewed the
> charter when deciding to participate.
> 
> The motivation is clear enough to me. But if a significant
> number of WG members want the charter changed, we can look
> into that.

My issue is this: Rob wants us to include factors that I think you
agree are outside the charter, but when uttering them, does not
mention re-chartering. Dealing non-RDF data has made at least the
wording of the requirements considerably harder. I'm in favor of
not dealing with them now, but if we are, I don't want put this
burden on the working group without the WG and the AC acknowledging
that we are undertaking a new job.

Defining how you query and report a set of triples in a database
must be much easier than defining how you query and report facts
which may have triple implications given sufficient other triple
and non-triple facts.

Perhaps the non-RDF query services can use DAWG-QL's tuple binding
syntax but not the graph reporting.
-- 
-eric

office: +1.617.258.5741 NE43-344, MIT, Cambridge, MA 02144 USA
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Received on Friday, 11 June 2004 19:12:09 GMT

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