W3C home > Mailing lists > Public > www-rdf-interest@w3.org > June 2002

Re: Implementing statement grouping, contexts, quads and scopes

From: Jonathan Borden <jonathan@openhealth.org>
Date: Tue, 25 Jun 2002 07:53:06 -0400
Message-ID: <055001c21c3e$df455c10$0a2e249b@nemc.org>
To: "Patrick Stickler" <patrick.stickler@nokia.com>, <areggiori@webweaving.org>
Cc: "RDF Interest" <www-rdf-interest@w3.org>, "RDF Logic" <www-rdf-logic@w3.org>

Patrick Stickler wrote:

> On 2002-06-24 20:58, "ext Jonathan Borden" <jonathan@openhealth.org>
> > The past version of the RDF MT WD discussed 'asserted triples' with the
> > implication that 'unasserted triples' might also exist. This language
> > removed in the current WD, so we must conclude that the current
intention of
> > the current RDF MT WD is that RDF reification in fact is not an
> > means of representing an 'unasserted triple'. If I am incorrect, the RDF
> > should state this relationship -- that is the purpose of a model theory,
> > isn't it?
> I agree. The MT would need to be tweaked to provide a resonable
> treatment of reification with regards to expressing unasserted
> triples, so as to provide for layering.

Ok. So then, in this case, one _could_ say that RDF reification is _a_
mechanism to represent the so-called "dark triples" (I prefer the term
"unasserted"), and hence "dark triples" have actually been present in RDF
all along.

The only quibble I would have with that is the syntax, but as you have
suggested, the syntax could be changed.

I understand, now, that your use of the N3 rule was intended to be used by a
"higher level" than RDF itself, e.g. by OWL, and agree. As long as RDF
provides a facility for unasserted triples, such mechanisms, as you have
exemplified, might exactly be used to "assert" as a fact, some triple that
had not been asserted by base RDF. Note that this is not a problem, because
the unasserted triple is not "negated" -- by being "unasserted" we are _not_
saying that the triple is _not true_ -- simply we are not assigning a truth
value at all -- at this level. Just as we do not assign truth values to the
character sequence ('n','o','t') until it is 'transformed' via the rules of
the english language to the symbol "not" which has meaning when used in

Received on Tuesday, 25 June 2002 07:58:26 UTC

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