W3C home > Mailing lists > Public > semantic-web@w3.org > June 2007

Re: owl:sameAs use/misuse/abuse Re: homonym URIs

From: Pierre-Antoine Champin <swlists-040405@champin.net>
Date: Thu, 14 Jun 2007 17:11:53 +0200
Message-ID: <46715AB9.6070307@champin.net>
To: Dan Brickley <danbri@danbri.org>
CC: Bernard Vatant <bernard.vatant@mondeca.com>, semantic-web@w3.org

Dan Brickley wrote:
> Bernard Vatant wrote:
>> Just to hit this owl:sameAs (ab)use nail a bit more.
>> Although I agree with Pat below (see my previous message) suppose I
>> (or Richard) disagree(s) and want(s) to stick to the assertion
>> http://dbpedia.org/resource/Berlin owl:sameAs
>> http://sws.geonames.org/2950159/
>> Does that mean that what I get from the two resources should be not
>> only consistent RDF descriptions, but *identical descriptions* ? I
>> guess so. It's clear that it's not the current case.
> The point is, according to the owl:sameAs claim, there aren't two
> resources, just one. One thing - with (at least two names (URIs). Asking
> an information system (such as the Web itself, or a library catalogue)
> about this thing could reasonably elicit different answers, depending on
> which name is used. That doesn't mean there are two things.
> Similarly, in the real world, different people and info systems known
> different things about me; they may even consider me to have different
> names/URIs. But there's only one me.

Consider that I work for two different companies (in the morning and in
the afternoon).
Both have a URI for me. Company 1 would state

comp1:champin emp:name "Champin" ;
              emp:salary "1000€" .

Company 2, on the other hand, would state

comp2:champin emp:name "Champin" ;
              emp:salary "2000€" .

using the same standardized properties, which happen to be functional.

It would seem legitimate to state that

comp1:champin owl:sameAs comp2:champin .

But that would lead to inconsistency (two different values for a
functional property).

Both URIs denote me, but not the same "me", only the "me" I am from the
point of view of each company.

Ambiguity is always lurking around.


> And so, anything true of me, is
> true of me. Some things might be true of one of my *names* (eg. that it
> is mentioned in a particular database). So yup, owl:sameAs is a pretty
> strong claim. Anything true of the one should be true of the other;
> because there is just the one.(*)
> Whether an HTTP GET that returns a 200 should always return the same
> thing, ... is an interesting question. It's certainly (if we believe the
> HTTP responses, and we believe the owl:sameAs claim) supposed to be
> considered an interaction with the same thing. But plenty of URIs return
> different or random or context-specific responses.
> http://spypixel.com/2006/spanglish/futurebot.cgi names the self-same
> resource as http://spypixel.com/2006/spanglish/futurebot.cgi (not
> becaues of owl:sameAs, but because it is the same URI :)  ... yet two
> GETs typically get different HTTP answers.
> Dan
> (*) tiptoing past philosophers of language here
Received on Thursday, 14 June 2007 15:11:59 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 1 March 2016 07:41:57 UTC