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Re: I have a trouble with The RDF Model

From: Graham Klyne <GK@Dial.pipex.com>
Date: Wed, 29 Nov 2000 20:59:09 +0000
Message-Id: <4.3.2.7.2.20001129204529.022abc80@pop.dial.pipex.com>
To: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>
Cc: ML RDF-interest <www-rdf-interest@w3c.org>
At 08:26 PM 11/28/00 +0100, Pierre-Antoine CHAMPIN wrote:
>This sentence has five words.
>This sentence is in english.
>This sentence begins with "This".
>This sentence talks about itself.
>
>Look at the RDF version of the last example above :
>
>  [stidD, stidD, rdf:subject, stidD]
>
>Funny, isn't it ?
>Not very useful, but definitely consistent.

Hmmm... I'm not sure, but that got me thinking.  What are the corresponding 
triples?  For:

   [r, p, s, o]

they would be:

   [p, s, o]
   [r, rdf:type, rdf:Statement]
   [r, rdf:predicate, p]
   [r, rdf:subject, s]
   [r, rdf:object, o]

So what about your self-referential statement?:

   [stidD, rdf:subject, stidD]

   [stidD, rdf:type, rdf:Statement]
   [stidD, rdf:predicate, stidD]
   [stidD, rdf:subject, rdf:subject]
   [stidD, rdf:object, stidD]

Well, it's loopy but I don't see a fundamental problem structurally.

This in turn caused me to review my thoughts about multiple models for a 
given statement.  Consider two 'quads':

   [r1, p, s, o]
   [r2, p, s, o]

What are the corresponding RDF triples?  I think:

   [p, s, o]

   [r1, rdf:type, rdf:Statement]
   [r1, rdf:predicate, p]
   [r1, rdf:subject, s]
   [r1, rdf:object, o]

   [r2, rdf:type, rdf:Statement]
   [r2, rdf:predicate, p]
   [r2, rdf:subject, s]
   [r2, rdf:object, o]

Note that the basic triple appears just once, even though it appears in two 
quads.  This, I think, is roughly what happens when id= is applied to an 
RDF property in its XML serialization.

Actually, the approach I've taken for my contexts ideas is slightly 
different:  the quad notation actually defines the reification, without 
asserting the statement triple.  A statement is asserted in a context by an 
RDF property that links the reification to the context.

#g

------------
Graham Klyne
(GK@ACM.ORG)
Received on Wednesday, 29 November 2000 16:06:24 GMT

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