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Re: URI ref comparison - clarification requested

From: Roy T. Fielding <fielding@gbiv.com>
Date: Thu, 26 Aug 2004 13:56:07 -0700
Cc: uri@w3.org
To: Danny Ayers <danny.ayers@gmail.com>
Message-Id: <5A172B70-F7A2-11D8-9EF3-000393753936@gbiv.com>

On Thursday, August 26, 2004, at 12:56  PM, Danny Ayers wrote:
>
> There appears (to me at least) to be some conflict between the
> definition of URI references in RFC 2396bis (sec 4.1) and that in RDF
> Concepts [1]. The latter says:
>
> "Two RDF URI references are equal if and only if they compare as
> equal, character by character, as Unicode strings.".
>
> I assume the 'ladder' of comparisons in 2396 applies to the URI
> references defined there.
>
> Is this a simple naming clash (URIrefs != RDFURIrefs) and/or is this
> an issue that should be raised on the RDF lists, or am I missing
> something obvious?

It is just poorly phrased in the RDF specification.  RDF can define
how RDF does comparisons of URI references in the processing of
assertions.  However, that definition does not change the fact that
two URI that are equivalent (by their very nature) may be falsely
determined to be different by the RDF algorithm -- that is the nature
of lossy optimizations.  This is not a problem when the URI references
are provided in a reasonably canonical form.

....Roy
Received on Thursday, 26 August 2004 20:55:48 UTC

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