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RE: requirement: rdfs query (for lack of a better name...)

From: Pat Hayes <phayes@ihmc.us>
Date: Fri, 7 May 2004 13:00:01 -0500
Message-Id: <p06001f2dbcc17cb2969e@[]>
To: Jos De_Roo <jos.deroo@agfa.com>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>

>OK Rob, sounds fine...
>(will sleep over it once more :))
>sounds like a separation of concerns

Right, exactly, and I think its a good separation.

Still, unlike Rob, I think that we could reasonably approach the 
'inference issue' by seeing if we can come up with some way for a 
query to indicate to a server (sorry I keep using this term, I can't 
think of a better one: the engine or entity to which the query is 
directed and which checks it against a graph: do we have a name for 
this?)  WHICH graph it wants the query to be directed to. Since 
'graph' here can be a virtual graph defined partly by inference 
closures (and may in fact be infinite in some cases, eg when thinking 
seriously about datatyped literals), a simple idea like just having a 
URI for each graph, or one graph per server, seems inadequate. So can 
we think of a way for a query to indicate which conceptual/virtual 
graph it is intended to be evaluated with respect to? For example 
(complete straw man) maybe the query could refer to a source listing 
a set of rules which the virtual graph is supposed to be closed 
under, or some such. Or it could be as coarse as just specifying 
plain/rdf/rdfs/datatyped as options, where each of these refers to a 
semantic extension and the graph is supposed to be closed under all 
inferences which are valid wrt that extension.


>Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
>"Rob Shearer" <Rob.Shearer@networkinference.com>
>07/05/2004 01:55
>         To:     Jos De_Roo/AMDUS/MOR/Agfa-NV/BE/BAYER@AGFA
>         cc:     <kendall@monkeyfist.com>, <public-rdf-dawg@w3.org>,
>         Subject:        RE: requirement: rdfs query (for lack of a 
>better name...)
>I'm suggesting that an RDF query language should not specify that the
>:Tony a :SEAFOOD
>exists. It's RDFS's job (or OWL's job, or SWRL's job, or something) to
>specify that.
>I'm suggesting that if there is some server sitting somewhere which
>happens to know this fact somehow (whether it derived it from RDF+RDFS
>or from somewhere else), then you should be able to query it.
>>  -----Original Message-----
>>  From: Jos De_Roo [mailto:jos.deroo@agfa.com]
>>  Sent: Thursday, May 06, 2004 4:36 PM
>>  To: Rob Shearer
>>  Cc: kendall@monkeyfist.com; public-rdf-dawg@w3.org;
>>  public-rdf-dawg-request@w3.org
>>  Subject: RE: requirement: rdfs query (for lack of a better name...)
>>  RobS wrote:
>>  [...]
>>  > Let's leave derived graphs and inferencing to working
>>  groups that know
>>  > how to address them and confine ourselves to representing queries
>>  > against the data model which underlies it all.
>>  Rob, I'm completely confused, do you really mean that one
>>  can't query
>>  :Tony a :CRAB.
>>  :CRAB rdfs:subClassOf :SEAFOOD.
>>  to get an answer like
>>  :Tony a :SEAFOOD
>>  ??
>>  (if no, then I go to bed... :))
>>  --
>>  Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/

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Received on Friday, 7 May 2004 14:00:04 UTC

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