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Comparing URIs and resources

From: Graham Klyne <gk@ninebynine.org>
Date: Thu, 10 Jul 2003 09:22:44 +0100
Message-Id: <>
To: Michael Mealling <michael@neonym.net>
Cc: uri@w3.org


I agree that equality of URIs is well understood (enough for most purposes).

At risk of (re)stating the obvious:  I think we should not conflate 
equality of *identifiers* (URIs) with equality of the *resources* that they 
identify, unless such conflation is to be stated explicitly as part of the 

My view is that, according to the URI specification, given two different 
URIs we simply do not know whether or not they identify the same resource.


At 13:04 09/07/03 -0400, Michael Mealling wrote:
> > Er, maybe I'm being rather forgetful here, but I don't recall that RFC2396
> > defines any notion of equality on resources.   I just checked all
> > occurrences of "equal" and none seemed to relate to equality of
> > resources.  Ditto "same".  Can you please point to the definition of
> > equality that you are using?
>The one implicit in the identity function: I.e. a URI is equal to
>I agree that is a very simple and limited form of equality but its the
>only one that's universal. Its so simple you could also get away with
>saying that there is no such thing as equality for URIs or
>I'm comfortable with either one since they're essentially the same
>property depending on whether your consider the identity function to
>also be an equality function.

Graham Klyne
PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
Received on Thursday, 10 July 2003 05:59:16 UTC

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