- From: Jonathan Borden <jonathan@openhealth.org>
- Date: Sat, 3 Aug 2002 18:51:44 -0400
- To: <www-tag@w3.org>, "Norman Walsh" <Norman.Walsh@Sun.COM>
----- Original Message ----- From: "Norman Walsh" <Norman.Walsh@Sun.COM> To: <www-tag@w3.org> Sent: Friday, August 02, 2002 3:37 PM Subject: Re: URIs: resources and contradictions was: Re: httpRange proposed text > > / "Jonathan Borden" <jonathan@openhealth.org> was heard to say: > | I would say what Joshua said even more strongly (this *is* a core > | principle): > | > | " > | When two people use the same URI to identify a resource _they are > | identifying the same resource_ > | " > | > | This is true by definition (indeed an axiom) > > I'm not sure how to reconcile your statement that this is > axiomatically true when I believe it is obviously false. > > | A: > | > | <http://example.org/car> rdf:type timbl:Document . > | <http://example.org/car> ex:length "1024" . > | > | and > | > | B: > | <http://example.org/car> rdf:type rf:Car. > | <http://example.org/car> ex:length "102" . > | > | rf:Car owl:subClassOf owl:Class . > | rf:Car owl:disjointWith timbl:Document . > | > | now let us assume that "ex:length" is a functional property e.g. that a > | resource may have only one value for this property. > | e.g. > | > | ex:length owl:subPropertyOf owl:FunctionalProperty . > | > | What do we have? > > Clear evidence that A and B did not identify the same resource when they > independently chose the name http://example.org/car > > | Well we have a few contradictions that's all, we are trying to say that: > | > | "1024" = "102" which is patently false > | and we are also trying to say both that http://example.org/car is both a > | timbl:Document and an rf:Car which is a contradiction if we also say that > | rf:Car owl:disjointWith timbl:Document . > | > | To summarize, a URI always identifies a single resource, regardless of who > | is using the URI and regardless of which claims are made about the resource. > > Ah, perhaps I get it after all: > > You have a reasoning system that uses URIs as identifiers. Because > that system is incapable of "knowing" anything about a URI other than > the string of characters that comprise it, it is axiomatic that if two > URIs are textually identical, they must mean the same thing. > > I think I can understand that. > > Is it widely accepted fact that this is a feature of all such > reasoning systems? Perhaps it is, I don't know. > > Be seeing you, > norm > > -- > Norman.Walsh@Sun.COM | To create a little flower is the labour of > XML Standards Architect | ages.--Blake > Sun Microsystems, Inc. | > >
Received on Saturday, 3 August 2002 19:07:26 UTC