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Re: Some TAG review of "Cool URIs for the Semantic Web"

From: Tim Berners-Lee <timbl@w3.org>
Date: Fri, 28 Sep 2007 13:50:49 -0400
Message-Id: <14712D2C-1F5B-4AB4-AD05-7E6576D6F7E7@w3.org>
Cc: "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>, Pat Hayes <phayes@ihmc.us>, Dan Connolly <connolly@w3.org>, Technical Architecture Group WG <www-tag@w3.org>, Susie Stephens <susie.stephens@gmail.com>
To: Harry Halpin <hhalpin@ibiblio.org>

On 2007-09 -28, at 10:54, Harry Halpin wrote:

> Williams, Stuart (HP Labs, Bristol) wrote:
> [snip]
>>>  But the key point is that the
>>> distinction has to do with whether it can be
>>> *accessed* by transfer protocols, rather than with the way it
>>> can be encoded or represented. The essential characteristics
>>> of a billboard can be conveyed in an image, but if the image
>>> has never been digitized then its not an information resource
>>> (yet).
> The problem is simple and practical: Given any "resource/thing"  
> that one
> wishes to talk about on the Web (i.e. using RDF, putting up web-pages,
> etc.), is given resource X an information resource or not?
>
> That's a question with real ramifications - i.e. should one use a 303
> redirect/# convention or not!


This is missing the point, I think.
Let's take what some might think of as an edge case: umm.. the  
declaration of independence.
One could imagine some discussion as to whether one means the paper  
thing or the document as information.

One could imagine a consistent world in which I say

<http://www.ushistory.org/declaration/document/images/ 
declarationscan.jpg> = <http://dbpedia.org/resource/ 
United_States_Declaration_of_Independence>.
(as in http://www.w3.org/2007/09/28-DoI.n3 )

Both are URIs of an information resource.

The first gives a 200 and a representation.  The second gives a 303  
and information which is not a representation of the information  
which *is* the DoI, but a document (one of many) about hte DoI.

This isn't a great example.  But the point is that the 200/303 isn't  
a question of what class of thing it is (identified by the URI) , so  
much as what the relationship between the response and the thing.   
 From the latter, the first follows.

Tim



PS: The 200 relationship the TAG calls 'Representation" in a very  
specific way, ... not in a general English way.  A tag:representation  
of a document is
an (if you like) encoding of its contents.   A conveyance of its  
meaning.  A tag:Representation is a pair of some metadata to tell  
you, among other things,  how to decode the bits, and some bits.

(Any attempt to  define these things in terms of common words is  
doomed to some confusion, as common words do not exist for the  
elements in the web architecture.
The AWWW therefore makes a partly self-referential definition of a  
system which works. )

PPS: The tabulator gets confused by the above when it comes to  
displaying the image, whcih is  a new tracked issue.









Received on Friday, 28 September 2007 17:51:12 UTC

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