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RE: URN as namespace URI for RDF Schema (run away... run away... ;-)

From: <Patrick.Stickler@nokia.com>
Date: Fri, 8 Oct 2004 10:19:13 +0300
Message-ID: <1E4A0AC134884349A21955574A90A7A50A1DF3@trebe051.ntc.nokia.com>
To: <JohnBlack@deltek.com>, <r.newman@reading.ac.uk>, <rhoadsnyc@mac.com>
Cc: <www-rdf-interest@w3.org>



> -----Original Message-----
> From: www-rdf-interest-request@w3.org
> [mailto:www-rdf-interest-request@w3.org]On Behalf Of ext John Black
> Sent: 07 October, 2004 16:53
> To: Stickler Patrick (Nokia-TP-MSW/Tampere); r.newman@reading.ac.uk;
> rhoadsnyc@mac.com
> Cc: www-rdf-interest@w3.org
> Subject: RE: URN as namespace URI for RDF Schema (run away... run
> away... ;-)
> 
> 
> 
> > From: Patrick.Stickler@nokia.com
> 
> [snip]
> 
> > The requesting client is not getting back a resource. It
> > is getting back a representation. And a given representation
> > can serve as the representation of more than one resource.
> > 
> > A representation can also be the representation of itself. 
> > 
> > I.e. a representation is the atomic component of the web, and
> > corresponds to a octet stream returned in the response to a
> > request. If the request URI denotes a representation, then
> > the representation returned is a representation of that
> > representation (resource) denoted by the request URI, and
> > thus the representation of a representation is always a 
> > bit-equal copy of itself.
> > 
> > So, the representation of a chair may be an binary encoded
> > image of the chair, yet that image is also a resource, and 
> > its representation is itself. Thus, the same representation
> > is the representation of two resources: the chair, and the
> > image (itself) and thus two GET requests with distinct 
> > request URIs denoting distinct resources can both return
> > the very same representation.
> > 
> > And, insofar as the semantics of the web machinery is
> > concerned, even when one gets back a representation of
> > a representation (such that one could fairly conclude
> > that one has gotten back the actual resource) one has
> > not actually gotten back the resource, only its 
> > representation.   
> 
> In my opinion, a better term for "representation of itself" is 
> "replication". It is lossless replication. I think of it as a 
> subclass of representation so as to fit in with the AWWW. So I 
> would say that the class of representations can be usefully 
> partitioned into those that are lossless replications and those 
> that are not. When a URI as symbol denotes a resource that 
> can be losslessly replicated by using that URI as retrieval 
> path we have a perfect name, a perfect reference, because it 
> creates perfect common knowledge of the denotation of that 
> name. Any one who knows the name, knows (algorithmically) the 
> resource denoted by the name. This reminds me of TimBL's position 
> on the http range issue. Because of these properties of URIs for 
> resources that can be losslessly replicated, i.e., HTTP URL URIs, 
> they do seem to deserve special recognition. 
> 
> Now the concept of bit-equal copy fits with the concept 
> of URI as retrieval path, but doesn't apply to URI as symbol. 
> And in RDF semantics URIs are names, not retrieval paths.

I think you misunderstood what I wrote. Perhaps you should
go back and re-read it. I think we're pretty much, if not
completely, in agreement here.

Patrick



> The denotation of a name is a bit of knowledge, and as such has 
> properties of knowledge, not properties of representation 
> retrieval. The difference between HTTP URL URIs as names for 
> resources that can be losslessly replicated and those URIs 
> that name resources that cannot be losslessly replicated is 
> a difference in knowledge. The semantic equivalence between two 
> instances of interpretation of the denotation of the URI is exact 
> in the former case and it is approximate in the latter case. 
> 
> It is like the difference between meeting someone at a 
> conference wearing her name on a name tag and looking at a 
> picture or reading a description of the person denoted by 
> that name. At the conference, the denotation of the name 
> is right there in person behind the name for all to know.
> Any other ways of representing or describing the denotation 
> of that person's name will always create approximations of 
> the knowledge that exists when the name is thus attached to 
> the person. 
> 
> John Black
> 
> > 
> > Cheers,
> > 
> > Patrick
> > 
> 
> 
Received on Friday, 8 October 2004 07:23:09 GMT

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