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Re: Concern with URI normalization text; proposed change

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 6 Apr 2004 11:08:52 -0500
Message-Id: <p06001f10bc988464fb2a@[]>
To: Tim Bray <tbray@textuality.com>
Cc: "Roy T. Fielding" <fielding@gbiv.com>, Jeremy Carroll <jjc@hplb.hpl.hp.com>, Pat Hayes <phayes@ihmc.us>, Graham Klyne <gk@ninebynine.org>, uri@w3.org

>On Apr 6, 2004, at 1:39 AM, Graham Klyne wrote:
>>Hmmm... my concern is that the unqualified claim of "strictly 
>>avoiding false positives" is also not factually true [1] and, if 
>>generic URI processing software is developed on this basis, could 
>>lead to incorrect results.  Is there another way to address this?
>Hmm... I think that the goal of "strictly avoiding false positives" 
>is indeed correctly stated.  To the extent that if there are 
>practices that would result in software that "climbs the ladder" in 
>good faith getting one, then those by definition are bad practices. 
>Today I'll dig up the latest draft and review
>>[1] http://lists.w3.org/Archives/Public/uri/2004Feb/0094.html
>>     (Look for "Section 6 (concern):")
>and try to think of an improvement.  False positives on URI 
>comparison would be very damaging to webcrawlers and caches and so 
>on and should really be avoided. -Tim

If I am following this discussion, we seem to be in violent 
agreement. Graham and Jeremy and I are concerned that URIref 
normalization may introduce name equivalences where RDF is expecting 
distinct names.  This would be very damaging, a potential disaster: a 
large part of the expected functionality of RDF and especially OWL is 
in determining that two names refer to one entity, and unpredictable 
normalization will wreck this kind of reasoning.

But that sounds like a 'false positive' (?), so it seems that we are 
all in agreement that it is important to avoid this situation, ie one 
where an application is expecting that two URI references are 
distinct, but a URI normalization process is licenced to convert one 
of them into the other 'silently', without giving notice.

I am not sure how this cashes out in actual words, but if we can all 
agree on the general point then perhaps the word-crafting will go 
more easily.

Pat Hayes

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Received on Tuesday, 6 April 2004 12:09:38 UTC

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