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RE: Do resources have representations?

From: <Patrick.Stickler@nokia.com>
Date: Mon, 28 Jul 2003 13:13:52 +0300
Message-ID: <A03E60B17132A84F9B4BB5EEDE57957B5FBC09@trebe006.europe.nokia.com>
To: <b.fallenstein@gmx.de>, <www-rdf-interest@w3.org>


I saw nothing in your summary that I would disagree with. In
fact, I think it captures the key issues. It's very similar
to a recent post of mine on the TAG list


And I see nothing wrong with your summary. 

You seem to think there is a problem lurking in there somewhere,
and I'd like to understand why?

Is there some particular behavior that might/does occur
that conflicts with this view?

Is there anything wrong with the target anchor being
implicit in the link, such that the href tag essentially
constitutes a function by which the URI is resolved to
some representation (possibly one of many)?



> -----Original Message-----
> From: ext Benja Fallenstein [mailto:b.fallenstein@gmx.de]
> Sent: 26 July, 2003 23:14
> To: rdf-i
> Subject: Do resources have representations?
> Hi all,
> I've noticed a thing about resources and representations that 
> strikes me 
> as peculiar.
> Let's say someone puts up a Web page containing the following:
>      ...seems like the <a href="http://www.w3.org/Consortium/">W3C</a>
>      is composed of a million monkeys typing on typewriters, whose
>      keepers occasionally publish those typescripts that look like
>      a technical specification...
> What does this <a> construct mean? What effect should it have in a 
> browser? From <http://www.w3.org/TR/html401/struct/links.html>:
>      This section introduces the link (or hyperlink, or Web link), the
>      basic hypertext construct. A link is a connection from one Web
>      resource to another. Although a simple concept, the link has been
>      one of the primary forces driving the success of the Web.
>      A link has two ends -- called anchors -- and a 
> direction. The link
>      starts at the "source" anchor and points to the "destination"
>      anchor, which may be any Web resource (e.g., an image, a 
> video clip,
>      a sound bite, a program, an HTML document, an element 
> within an HTML
>      document, etc.).
>      [...]
>      The default behavior associated with a link is the retrieval of
>      another Web resource. This behavior is commonly and implicitly
>      obtained by selecting the link (e.g., by clicking, 
> through keyboard
>      input, etc.).
>      [...]
>      href = uri [CT]
>          This attribute specifies the location of a Web resource, thus
>          defining a link between the current element (the 
> source anchor)
>          and the destination anchor defined by this attribute.
> By "retrieval of [a] resource," I presume the spec means 
> "retrieval of a 
> representation of a resource." So the link points to a 
> resource, and if 
> I click on the link, my browser is expected to show me some 
> representation of this resource (it doesn't specify which 
> representation).
> Assume that http://www.w3.org/Consortium/ identifies an organization, 
> the World Wide Web Consortium. Assume that I have assigned 
> http://example.org/~benja/w3c to denote the same organization. Both I 
> and the owners of w3.org have provided authoritative information from 
> which it is clear that the two URIs identify the same resource.
> We can then clearly conclude that
>      <http://example.org/~benja/w3c> = 
<http://www.w3.org/Consortium/> .

Assume that it is true that

     <http://example.org/~benja/w3c> hasRepresentation
         "W3C -- the standards body for Web technologies." .

Then it is also true that

     <http://www.w3c.org/Consortium/> hasRepresentation
         "W3C -- the standards body for Web technologies." .

(which is not the content of the Web page behind that URI).

Given that the link in the example above, according to the HTML spec, 
points to the *resource*, does this mean that it would be acceptable for 
a browser to serve me "W3C -- the standards body for Web technologies" 
as a representation of the link target? Clearly not.

It seems to me that the current situation is,

- a URI corresponds to a set of representations
- a URI denotes a resource
- two URIs denoting the same resource can correspond to different sets 
of representations
- if I link to a URI through HTML, my intention is not only to specify 
the resource I link to, but also the set of representations that is 
shown to a user when they click on the link.

[In a sense, not the resource has a retrievable set of representations, 
but the URI that denotes the resource.]

Obviously there's something wrong with this picture, but I don't know 
how to fix it.

- Benja
Received on Monday, 28 July 2003 06:14:45 UTC

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