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Re: Named graphs etc

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 10 Mar 2004 11:08:34 -0600
Message-Id: <p06001f40bc74fa345fae@[]>
To: Patrick Stickler <patrick.stickler@nokia.com>
Cc: "ext Chris Bizer" <chris@bizer.de>, <www-archive@w3.org>, <jjc@hplb.hpl.hp.com>

>On Mar 09, 2004, at 20:20, ext Pat Hayes wrote:
>>... Since there are no deployed ways of distinguishing asserted 
>>from non-asserted publications, it seems unlikely that the planet 
>>will now decide that all the published OWL and RDF and RDFS is all 
>>just kind of lying there until someone finds a way to get it 
>I expect there will be degrees of trust. Legacy RDF/OWL with no 
>explicit statement
>about whether it is or is not asserted will probably be trusted less 
>(or not at all
>for some applications) than RDF/OWL using new mechanisms to express 
>assertion and
>other qualifications.
>As the machinery evolves, legal agreements will likely mandiate 
>explicit qualification
>of graphs used in interchange of knowledge falling under the terms 
>of such agreements.
>Over time, one could expect there will be fewer and fewer graphs 
>with no qualification
>>RDF is a pretty weak foundation already, and we have overloaded it 
>>just by putting OWL on it. It can't take any more :-)
>Would constraining the interpretation of a given class of properties to
>the graphs containing the statements in which they occur be overloading

Yes, I think so. It would require the entire MT to be rewritten, to 
do it rigorously. It basically introduces indexicals into the 
language.  And it has all kinds of odd operational consequences for 
inference engines; for example, in OWL, how would you know whether or 
not two graphs references were referring to the same graph?

>Or would this rather be more of an application layer above,
>but not directly impacting RDF/OWL?
>>... what is more minimal than a single XML tag?
>It depends. For TriX, that is easy. And in fact, TriX *already* provides
>that attribute, and has since the first published version.
>But for RDF/XML, you aren't honestly proposing a change already?! ;-)

Maybe Im not familiar enough with XML, but would adding a property to 
an element amount to a substantial change to RDF/XML? Seems kind of 
piffling to me. I assumed one could always add properties without 
breaking anything.

>Also, a single XML attribute is easy for one serialization, but what about
>all the other forms of expression? N3, Turtle, TriX, Squish, TriQL, 
>RDQL, etc. etc.

Well, good point, although the QLs are kind of irrelevant since one 
wouldnt expect to be asserting a query.


>True, if the addition of a single syntactic flag can be proven to
>provide a solid foundation for bootstrapping higher layers of trust
>and authentication, then folks might be convinced to change all those
>serializations, but I doubt it.
>I think the vocabulary approach is both an easier sell, and also
>the more "pure" RDF solution (if the semantics are doable).
>>>The fact that the WG Tests are not asserted is found in the Test Cases
>>>Recommendations (not that they say so explicitly).
>>I propose that the way this will actually get done is that their 
>>objective publication status is vague and underdefined, but since 
>>they have no warrant, no serious agent is going to take them on 
>>trust as asserted, which is all that will matter.
>Right. This correlates, I think, to what I said above about degrees
>of trust for non-qualified, non-authenticated graphs.
>Patrick Stickler
>Nokia, Finland

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Received on Wednesday, 10 March 2004 12:08:36 UTC

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