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Re: subgraph/entailment

From: Enrico Franconi <franconi@inf.unibz.it>
Date: Tue, 6 Sep 2005 01:49:49 +0200
Message-Id: <B9F30ED8-3806-4BCF-A73B-87E13B0D7495@inf.unibz.it>
Cc: Andy Seaborne <andy.seaborne@hp.com>, RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: Dan Connolly <connolly@w3.org>

On 6 Sep 2005, at 00:56, Dan Connolly wrote:
> On Sep 5, 2005, at 5:20 PM, Enrico Franconi wrote:
>> I don't see why we need to maintain in the document the wording  
>> "subgraph of"; we could write "entailed by" and say that the type  
>> of entailment is decided by the service.
>> Why not?
>
> So at this point, if you want the WG to consider a different  
> design, the
> burden is on you give new information that motivates reconsidering
> earlier decisions.

It is not new information.
More than one year ago, I made the very same argument in:
<http://lists.w3.org/Archives/Public/public-rdf-dawg/2004JulSep/0066>
and
<http://lists.w3.org/Archives/Public/public-rdf-dawg/2004JulSep/0069>.
They were my only important contributions last year :-)

And we are not proposing any new design, just changing a word that  
according to the logs already switched three times in the past.

>>> The current text in rq23 is based on the second paradigm.  Would  
>>> it help to add text that explains that the subgraph is the  
>>> subgraph of the entailed graph, not the ground data?
>>
>> No, as I said it does not work in important cases.
>
> Which cases are those? I scanned the thread and I don't see what  
> you're
> referring to.

The whole point is about future interoperability of SPARQL with any  
sort of ontology language that will ever exist beyond RDF. For the  
purpose of querying RDF graphs the current version it is fine and  
satisfies of course the provided use cases, but this does not leave  
space for adopting SPARQL in strictly related but richer contexts.  
And note that we are talking here of languages that share the same  
data model, namely RDF graphs. So, we are *standardising* (what a big  
responsibility) a query language for a specific data model, that does  
not work by design for its already standardised (by the same body,  
W3C) extensions. This seems a bit weird to me.


And don't forget that there are still two major outstanding issues  
from my original comment: minimality of answers and safeness of queries.

cheers
--e.
Received on Monday, 5 September 2005 23:50:01 GMT

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