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Re: Review of "Cool URIs for the Semantic Web"

From: Richard Cyganiak <richard@cyganiak.de>
Date: Wed, 29 Aug 2007 13:08:32 +0200
Message-Id: <987DEE27-5223-439C-8CC9-519A7FEDA140@cyganiak.de>
Cc: <www-tag@w3.org>, "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>, "Leo Sauermann" <leo.sauermann@dfki.de>
To: "Booth, David (HP Software - Boston)" <dbooth@hp.com>


On 28 Aug 2007, at 20:52, Booth, David (HP Software - Boston) wrote:
> I missed Stuart's review of this "Cool URIs" document
> http://www.dfki.uni-kl.de/~sauermann/2006/11/cooluris/
> when I was away on vacation, but recently saw reference to it and  
> wanted
> to comment on one statement.
>> From: Williams, Stuart (HP Labs, Bristol)
>> [ . . . ]
>> wrt "Be on the web": "Given only a URI, machines and people should be
>> able to retrieve a description about this URI from the web. ..."   
>> This
>> is a little too loose, in that the description is not about
>> the URI but about the resource to which the URI refers.
>> [ . . . ]
> While I assume that the above statement reflects the TAG's accepted
> thinking on this topic to date, I think it is actually somewhat
> incorrect, and the original phrasing by the Cool URIs authors was
> actually better.
> To illustrate why, suppose you receive a URI http://example.org/ 
> moon and
> you wish to find out what resource it refers to.  (It refers to the
> moon, but you don't know that yet.)  You dereference to find that it
> 303-redirects to http://example.org/moon-description.html which serves
> only the following statements:
> 	http://dbooth.org/2007/moon/ is a moon.
> 	http://dbooth.org/2007/moon/ orbits the Earth.
> Those statements describe the resource (the moon) even though they do
> not happen to be using the same URI to refer to it.  (Bear in mind  
> that
> more than one URI can refer to the exact same resource.  In fact, in
> this case http://dbooth.org/2007/moon/ owl:sameAs
> http://example.org/moon , but you do not know that yet.)  Clearly, the
> returned page is inadequate for helping you understand what resource
> http://example.org/moon is intended to denote, even though the above
> statements describe the *resource* perfectly well.

As Stuart pointed out in this thread, we do indeed want a description  
of the *resource* (it is made of cheese) and not a description of the  
*URI* (it is 23 characters long). You are right, the description must  
use the original URI to be useful for our purposes, but I think this  
point is sufficiently clear from the document. (E.g. a few pages  
further down: “Each of the RDF documents would contain statements  
about the appropriate resource, using the original URI, e.g. http:// 
www.acme.com/id/alice, to identify the described resource.”)

The latest online version of the document has already been updated to  
address Stuart's comments.

Nevertheless, I think that the notion of a “URI declaration” is  
interesting and helpful as a shorthand for this whole  
“dereferenceable 303/hash-enabled HTTP URI for non-information  
resources” business. Indeed our document can be summarized as:  
“Semwebbers, please declare your URIs! Here's how to make URI  
declarations with plain HTTP.”


> In fact, the *only*
> thing that is lacking about this resource description is the fact that
> the described resource is also intended to be *associated* with the  
> http://example.org/moon .
> The right to establish such an association belongs to the URI  
> owner, as
> described in WebArch section
> http://www.w3.org/TR/webarch/#def-uri-ownership
> [[
> URI ownership is a relation between a URI and a social entity, such  
> as a
> person, organization, or specification. URI ownership gives the  
> relevant
> social entity certain rights, including:
>    1. to pass on ownership of some or all owned URIs to another
> owner-delegation; and
>    2. to associate a resource with an owned URI-URI allocation.
> ]]
> Thus, information that establishes this association is intrinsically
> about the URI itself -- *not* merely about the resource.  This is the
> idea behind a URI declaration, as described in this document:
> http://dbooth.org/2007/uri-decl/
> I would encourage the TAG to consider these ideas, and welcome any
> comments on this document.
> Thanks,
> David Booth, Ph.D.
> HP Software
> +1 617 629 8881 office  |  dbooth@hp.com
> http://www.hp.com/go/software
> Opinions expressed herein are those of the author and do not represent
> the official views of HP unless explicitly stated otherwise.
Received on Wednesday, 29 August 2007 11:10:06 UTC

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