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RE: New version of URI Declarations [Usage scenarios]

From: Booth, David (HP Software - Boston) <dbooth@hp.com>
Date: Sat, 1 Mar 2008 06:58:33 +0000
To: Pat Hayes <phayes@ihmc.us>
CC: "www-tag@w3.org" <www-tag@w3.org>
Message-ID: <184112FE564ADF4F8F9C3FA01AE50009E78E0BF811@G1W0486.americas.hpqcorp.net>

> From: Pat Hayes [mailto:phayes@ihmc.us]
>
> At 2:23 AM +0000 2/29/08, Booth, David (HP Software - Boston) wrote:
> >Hi Pat,
> >
> >I think I see your point: without me standing in front of you,
> >pointing to the moon and saying: "I hereby declare that
> >http://dbooth.org/2007/moon/ henceforth refers to *that* moon", my
> >URI declaration cannot be guaranteed to be understood as referring
> >to the actual moon.
> >
> >That sounds like a valid point, but it doesn't invalidate the notion
> >of a URI declaration.
>
> It does invalidate what you say about it, however. And I wonder quite
> what is the point of it, if it can't do what you say it is intended
> to do.

I will try to improve the description.   I'm not well versed in formal semantics, so any suggestions for improving the rigor and precision of my explanations would be most welcome.

The point of a URI declaration is to have a clear mechanism for a URI minter to indicate to others what resource a URI is intended to denote.  Operationally, it does this by indicating a particular set of assertions -- the "core assertions" -- that should be accepted if the URI is used.  These assertions are intended to delimit the range of possible interpretations of what the denoted resource might be -- ideally uniquely determining the resource, but (a) that depends on the quality of the assertions, and (b) as you pointed out, ultimately there is no way to ensure that a user's actual interpretation is the same as the minter's intent.

>
> >Mechanically, a URI declaration really only creates an association
> >between a URI and a set of assertions (the "core assertions").
>
> Well, OK, but now I would ask, why do we need anything special to do
> this? Publishing some OWL and giving the document a URI does this
> already. So whats so special about the new idea?

The idea isn't new.  What's new is the term "URI declaration" and the specific focus on what it is, why it is relevant and how it should be used.

>
> >The interpretation of those assertions as describing a particular
> >resource  -- whether you interpret them the same way I do -- is a
> >different issue.  That problem exists regardless of whether one
> >accepts the notion of URI declaration.  URI declarations do not try
> >to solve that problem.
>
> So, what problem DO they solve?

The notion of a URI declaration helps answer questions like the following.

SCENARIO 1: Fred wishes to publish some RDF assertions about a particular protein.  He notices that Alice, Beatrice and Carl have already published assertions about the protein, and they all use the same URI to denote that protein: the URI minted by Alice.  Fred notices that if he uses Alice's URI to denote the protein, his assertions will be logically inconsistent with some of Alice's assertions, although they are logically consistent with Beatrice and Carl's assertions.  He wonders whether he should publish his assertions using Alice's URI -- and post a blog entry noting that his assertions should not be used in conjunction with Alice's assertions -- or mint a new URI.

Question: Should Fred use Alice's URI?

Answer: No.  He should mint a new URI and indicate the relationship (not owl:sameAs) to Alice's URI -- at least rdfs:seeAlso.

SCENARIO 2: Daria also wishes to publish some RDF assertions about the same protein and wonders if she should mint a new URI.  She notices that her assertions are logically consistent with Alice's assertions, but not with Beatrice or Carl's.

Question: Should Daria use Alice's URI?

Answer: Yes, though she MAY mint a new one.

SCENARIO 3: Erin has accumulated some observations about a different protein, and she wishes to publish them as assertions.  Some of them are merely assertions that serve to uniquely identify the protein that she wishes to talk about.  Others are observations about the protein's behavior.  She is very confident about the correctness of the first set of assertions, but no so confident about the assertions about the protein's behavior.  She mints a URI http://example/erin/proteins#p4 for the protein and wonders whether she should publish all of her assertions in one OWL document at http://example/erin/proteins, or separate them into two documents.

Question: Should Erin put all of these assertions in a single document?

Answer: No.  Erin should separate them into two documents.  The assertions that uniquely identify the protein should be placed at http://example/erin/proteins, and should include an rdfs:seeAlso that points to another document containing the other assertions.



David Booth, Ph.D.
HP Software
+1 617 629 8881 office  |  dbooth@hp.com
http://www.hp.com/go/software

Opinions expressed herein are those of the author and do not represent the official views of HP unless explicitly stated otherwise.
Received on Saturday, 1 March 2008 07:00:17 GMT

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