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Re: My action item on Moby Dec, issue 14, etc

From: Stefan Eissing <stefan.eissing@greenbytes.de>
Date: Mon, 23 Sep 2002 12:57:45 +0200
Cc: "Williams, Stuart" <skw@hplb.hpl.hp.com>, "'Michael Mealling'" <michael@neonym.net>, www-tag@w3.org
To: "Roy T. Fielding" <fielding@apache.org>
Message-Id: <4A39B42C-CEE3-11D6-8A96-00039384827E@greenbytes.de>


Am Freitag den, 20. September 2002, um 20:52, schrieb Roy T. Fielding:

>
>> Even seen it asserted in many places that a URI unambiguously 
>> identifies a
>> single resource. I've not seen it asserted the other way round... 
>> that a
>> resource is identified by a single URI. Such an assertion might be a
>> consequence of a definition of resource like Roy's about a 
>> resource being a
>> conceptual mapping over time between an identifier and a set of 
>> time varying
>> equivalent representations.
>
> Nope, it is N:1.  My definition of a resource does not say how many URI
> identify that resource.  I don't even mention them in the same 
> paragraph.

In another thread on the uri list, you pointed out that:

"The mapping [of URIs] is the resource and the resource always 
exists,[...]"
[1]

In terms of Tim Bray's alternatives (either the resource is the uri (a)
or it is a separate concept(b)) you seem to allow for both to be true.

I get the feeling I missed something here. Could you explain?

//Stefan

1. http://lists.w3.org/Archives/Public/uri/2002Sep/0024.html

>>> An N:1 mapping of a URI to a Resource
>>> would require some way to determine more information about a Resource
>>> other than its URI and that information does not exist at this layer
>>> of the architecture.
>
> No it wouldn't -- it merely recognizes their existence so that such
> understanding can be used at other layers.  HTTP had a mechanism at one
> point that would have provided information about the other N, but it
> was removed due to lack of consensus.  CDN depends on similar notions.
>
> Besides, right now we are talking about a document that already covers
> many layers at the same time.
>
> .....Roy
>
>
Received on Monday, 23 September 2002 06:58:21 GMT

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