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Generic-Resources-53: URIs for representations

From: Williams, Stuart \(HP Labs, Bristol\) <skw@hp.com>
Date: Mon, 2 Oct 2006 15:31:50 +0100
Message-ID: <C4B3FB61F7970A4391A5C10BAA1C3F0D2B9CE2@sdcexc04.emea.cpqcorp.net>
To: <raman@google.com>
Cc: <www-tag@w3.org>

I happened on "On Linking Alternative Representations To Enable
Discovery And Publishing" [1] in a way that casued be to read through
the draft. I've got what I think is an editorial comment about
consistency of use of the term "representation" with respect to the way
it is used in webarch.

I think that in creating webarch [2] we tried to maintain a fairly clear
distinction between resources and representations (modulo anything can
be a resource!). In that world view, IIRC, it was "resources" rather
than "representations" that have URIs. In particular, IIRC, we framed
representations as an ephemeral things ('bits' on a wire) that are
exchanged between web clients and origin servers.

At 2.1 this draft asks:

"Given resource http://example.com/ubiquity/resource with corresponding
representations for a desktop browser, a PDA and a cell-phone, should
these different representations: 

 - Have distinct URIs?
   ^^^^^^^^^^^^^^^^^^
 - Have a single URI that delivers the appropriate representation?

 - If publishing distinct URIs for the resource and its various
representations,
 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
   how should the relationship between these URIs be expressed in a
discoverable, 
   machine-readable form? How should this relationship be reflected in
the hyperlink 
   structure of the Web?"

The language through the rest of the finding tends to speak in terms of
representations as things that can have URIs: eg.

	2.1.1 Suggested Solution
	We suggest the following approach for this situation: 

	1. Create representation-specific URIs for each available
representation 
	   (representation_i), e.g.,
http://example.com/ubiquity/resource/representation_i.

	... 

	4. ...using a redirect to the URI of a specific
representation...

	5. Use linking mechanisms provided by the representation being
served 
	   to create links to the other available representations. ...

	4 Conclusions
	Principal conclusions:

	...Thus, each representation of interest should get it's own URI
and 
	there should be one additional URI representing the generic
resource.


I'm not sure how I would suggest squaring this, other than to suggest
that the alternate URI (ie. non-generic URI) are references to alternate
resources that serve up appropriate, specific, variant representions of
the corresponding generic resource.

Best regards

Stuart Williams
--
[1] http://www.w3.org/2001/tag/doc/alternatives-discovery-20060915.html
[2] http://www.w3.org/TR/webarch
Received on Monday, 2 October 2006 14:32:20 GMT

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