- From: Pierre-Antoine Champin <swlists-040405@champin.net>
- Date: Thu, 14 Jun 2007 17:11:53 +0200
- 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. pa > 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