W3C home > Mailing lists > Public > www-rdf-interest@w3.org > December 2003

RE: Trust, Context, Justification and Quintuples

From: Graham Klyne <gk@ninebynine.org>
Date: Fri, 19 Dec 2003 17:56:19 +0000
Message-Id: <5.1.0.14.2.20031219175229.024b41c8@127.0.0.1>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, "Chris Bizer" <chris@bizer.de>, <www-rdf-interest@w3.org>

At 13:31 19/12/03 +0100, Jeremy Carroll wrote:
>I suggest that instead of a quadruples or quintuples approach that this
>difference in semantics is better reflected by naming graphs (sets of
>triples).

FWIW, this is just what I do in my current software.

But I note that it is, in information terms, pretty much equivalent to 
using quads, where the 4th item is a context id.

quads->labelled graphs:
   collect statements by context id
   use context id as graph label
   put statements, without context id, into appropriately labelled graph

labelled graphs->quads:
   for each statement of each labelled graph:
     construct a quad that is the statement
     PLUS the graph identifier as its context id

It's informally stated, but I think that's a bijection.

But, then you say:
>whose to say that there is not another quad somewhere

I think you have a point here, but I'd also ask:

Who's to say that one of your named graphs doesn't have another triple 
somewhere?

Or, to put it another way, what do you do with:

ID => { < a, b, c >
         < a1, b1, c1 >
         < a2, b2, c2 > }

ID => { < a3, b3, c3 > }

?

#g
--

BTW, Chris, in my original response to you, I didn't advocate using 
reification (though I did once argue its use as a way to abstractly 
represent quads in "pure" RDF).



------------
Graham Klyne
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Received on Saturday, 20 December 2003 05:16:25 GMT

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