W3C home > Mailing lists > Public > www-tag@w3.org > August 2003

Re: httpRange-14

From: Bill de hÓra <dehora@eircom.net>
Date: Sat, 02 Aug 2003 12:33:36 +0100
Message-ID: <3F2BA190.4070802@eircom.net>
To: Tim Berners-Lee <timbl@w3.org>
CC: "Roy T. Fielding" <fielding@apache.org>, Norman Walsh <Norman.Walsh@Sun.COM>, Public W3C <www-tag@w3.org>

Tim Berners-Lee wrote:

Tim,

> Sorry, but the semantic web architecture absolutely needs the idea
> of information resources. The RDF identifier foo#bar is
> used by dereferencing foo and parsing it a get information.

Is it? I'm sure there are fragids out there that are being used as 
just proper names. And when it comes to machine reasoning, that is 
/all/ they are. The RDF MT explicitly does not care abut URI 
structure. You can't carry over that implication without going 
beyond the RDF MT. An RDF machine that did this would be embracing 
and extending RDF semantics in much the same way cwm does.

To state, in a machine reasonable way that a URI denotes an 
information resource rather a non-information resource requires an 
ontology of resources - URI indexicals are not sufficient.

If you are going to mandate a privileged status for URIS with 
fragids in the semantic web, then before the URI is forwarded to an 
RDF MT compliant reasoner that URI needs to be annonated with new 
triples that claims it is an information type resource. So, you 
/still/ need the resource ontology.

This automagic must be stated explicitly in the architecture, as 
being automagic. That's not to say it isn't useful, people hack at 
URI structures every day to great effect, but as things stand it's 
beyond RDF and any semantic web MT I've seen.

And I suspect this opens a Pandora's box of hacks, optimizations, 
localizations, my-need-is-special, non-portable extensions and 
presumptions to the semantics that involve frigging with URIs. You 
name it. This is since I don't see why we'd would stop carving 
things up at information resources, if that turned out to be useful.

If so, where this heuristic annotating is done needs to be clearly 
outlined. Is there a layer for it?

The more I think about it, the more this seems like a way of 
avoiding defining a new URI scheme for the semantic web by finessing 
the opacity axiom.


Bill de hÓra
Received on Saturday, 2 August 2003 07:33:49 UTC

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