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Fwd: Re: ISSUE-148: IRIs do *not* always denote the same resource

From: Guus Schreiber <guus.schreiber@vu.nl>
Date: Thu, 19 Dec 2013 23:17:00 +0100
Message-ID: <52B3705C.5020103@vu.nl>
To: RDF WG <public-rdf-wg@w3.org>

You probably saw the message from David Booth about ISSUE-148 on the 
comments list.  In the W3C spirit of doing the ultimate for consensus I 
created a straw poll to get  your opinions on the amendment he proposes. 
Based on the outcome the chairs will make a suggestion  whether or not 
further action is called for.

The straw poll is here (and open until the end of the year):


Enjoy your Xmas break.

-------- Original Message --------
Subject: Re: ISSUE-148: IRIs do *not* always denote the same resource
Resent-Date: Thu, 19 Dec 2013 20:26:55 +0000
Resent-From: <public-rdf-comments@w3.org>
Date: Thu, 19 Dec 2013 15:26:22 -0500
From: David Booth <david@dbooth.org>
To: Guus Schreiber <schreiber.guus@gmail.com>
CC: Public RDF comments list <public-rdf-comments@w3.org>

On 12/18/2013 09:33 PM, David Booth wrote:
> On 12/18/2013 05:47 PM, Guus Schreiber wrote:
>> David,
>> The RDF WG resolved today [1] ISSUE-148:
>  > Resolve ISSUE-148 by changing the "IRIs have global scope"
>  > bullet point in section 1.3 in Concepts to "By design,
>  > IRIs have global scope. Thus, two different appearances
>  > of an IRI denote the same resource. Violating
>  > this principle constitutes an IRI collision
>  > [WEBARCH]." http://www.w3.org/TR/webarch/#URI-collision
>  >
>  > We very much hope you can live with this outcome. It might
>  > not be exactly what you wanted, but I hope it is at least
>  > very close to it.
> Indeed, this is close, but it still does not address my concern,
> because it still says "two different appearances of an IRI
> denote the same resource" as though that is always true, in
> spite of fact that the next sentence acknowledges that this
> can be violated (though it gives no clue about how).
> I gather that someone didn't like the word "should" or the
> phrase "is intended to" that were proposed earlier.   As a
> compromise, how about inserting "RDF assumes that":
>    "By design, IRIs have global scope. Thus, RDF assumes
>    that two different appearances of an IRI denote the same
>    resource. Violating this principle constitutes an IRI
>    collision [WEBARCH]."
>    http://www.w3.org/TR/webarch/#URI-collision
> David

P.S. According to the meeting minutes,
the WG **did not even consider** any wordings that would have fully
addressed the concern that caused me to raise this issue.  The only two
options that were considered were *identical* in still having the
problem described above.

I know it isn't easy to craft verbiage that is acceptable to many
different parties with different perspectives, and I have offered to
help do that.  But the way the working group has handled this --
simultaneously prohibiting discussion on the public-rdf-comments list
while also prohibiting non-member subscription to the working group
discussion list -- has left me only an extremely blunt instrument for
communicating with the working group.  In essence, all I can do is raise
a formal objection.  And friends, that's rather broken.  It sure ain't
very efficient.

This is the time to get this fixed.  We should not go another 5 years
with wrong/misleading statements about the uniqueness of IRI reference,
leading new RDF users down a garden path only to be surprised and
disappointed later when merged graphs don't work as expected.  One might
assume that, because this text is a non-normative introduction, it isn't
very important.  But it *is* important because it affects how the reader
thinks about the whole specification.  Readers need to know that URI
collisions can happen **even with RDF that is 100% compliant with the
RDF specification**.

The currently adopted verbiage *almost* addresses my concern, because it
acknowledges that the principle of unique URI reference *can* be
violated.  But alas, as currently phrased, readers are likely to assume
that such violations are violations of the RDF specifications, rather
than violations of a higher level architectural objective.  Readers need
to know that RDF makes the *assumption* of unique URI reference, and
hence if this assumption is violated, there may be problems due to URI

I have spent a *lot* of time over the past several years -- probably
*thousands* of hours cumulatively -- trying to get to the bottom of the
resource identity issue.  In fact, I may have spent more time on this
issue than all other members of the RDF working group *combined*,
excluding Pat Hayes!  But that is mere idle speculation.  The point is
that although this may seem like a trivial issue to some, it is
important to me, as to my mind it ultimately underlies nearly
*everything* we do in the Semantic Web that we're trying to build.

I have done my best to work as efficiently as possible with the RDF
working group -- moving lengthy discussions to other lists, trying hard
to reach common understanding with other individuals before proposing
fixes that might reach consensus, and offering to help craft acceptable
wording -- but as explained above, the constraints imposed by the
working group have made the process frustratingly difficult and awkward.

So, I guess I will rephrase my suggestion above.  Would anyone strongly
*object* to inserting "RDF assumes that" in the currently adopted bullet
phrasing, as described above?  If so, why?

Received on Thursday, 19 December 2013 22:17:29 UTC

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