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Re: Re[2]: Summary: Section 2: What does a URI identify?

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Wed, 20 Mar 2002 09:02:44 +0000
Message-Id: <>
To: "Roy T. Fielding" <fielding@apache.org>, "Williams, Stuart" <skw@hplb.hpl.hp.com>
Cc: "'Jonathan Borden'" <jonathan@openhealth.org>, Paul Grosso <pgrosso@arbortext.com>, www-tag@w3.org, Chris Lilley <chris@w3.org>
At 19:54 19/03/2002 -0800, Roy T. Fielding wrote:

A fragment
>is a separate identifier -- a user-specifiable indirect identifier that
>allows identification of a portion of any representation, within the set
>of available representations, of a given resource.

May I seek some clarification here.  You say that a fragment identifier 
*allows* identification of ...

That "allows" is wee bit wiggly.  The question that RDF needs answered is 
"What does a URI reference, with a fragment identifier, identify."

For a set of things to be identifiers, there must be function whose domain 
is the set of identifiers.  In the case of URI references with fragment 
identifiers, is there such a function and what is its range?

It might be helpful to consider a specific example:

http://www.w3.org/ identifies a resource.  What does http://www.w3.org/# 

>   In other words, it
>allows a third party to identify the product of a retrieval action,
>or some portion of that product, indirectly via the resource URI.
>In general, that is something you want to avoid doing unless there is
>no other available means for directly identifying it as a resource
>with its own URI.

Is it possible to construct an algorithm which will convert an arbitrary 
URI reference into a URI?  I suggest that it is, and thus it is possible to 
create a URI for whatever is identified by any URI reference.  Is that a 
sufficient condition for whatever is identified by a URI reference to be a 

Received on Wednesday, 20 March 2002 04:04:41 UTC

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