- From: Graham Klyne <Graham.Klyne@Baltimore.com>
- Date: Fri, 11 May 2001 15:54:25 +0100
- To: Dan Connolly <connolly@w3.org>
- Cc: Martyn Horner <martyn.horner@profium.com>, w3c-rdfcore-wg@w3.org
At 03:31 AM 5/8/01 -0500, Dan Connolly wrote: > Can two different URI's name the same resource? > >but I think it can actually be reduced to a test case: > >/====== >@prefix u: <http://www.w3.org/2000/01/rdf-schema#>. > ><#Car> u:subClassOf <#Automobile>. ><#Automobile> u:subClassOf <#Car>. >\====== > >(attached as RDF/xml, cloaked as text/html) > >If we decide that subClassOf works like conventional subset >(cf > http://www.w3.org/2000/03/rdf-tracking/#rdfs-no-cycles-in-subClassOf >) then we can conclude from the above that (the absolute >forms of) #Car and #Automobile denote the same resource. > >I suggest the answer is: yes. But this only works for resources that are 'rdf:Class'es. It says these two classes describe (have as instances) the same set of resources. My view of resource equivalence is more like the "walks like a duck, ..." test: If all queries using two different URIs always return the same result, then the URIs in some sense designated "equivalent" resources. I think it's an open question (or a matter of definition rather than deduction) whether these are actually the same resource. I suppose that if we had a model theory we could answer that question by determining whether the URIs denoted the same member in the domain of discourse. And I suspect that different model theories could give different answers. #g ------------------------------------------------------------ Graham Klyne Baltimore Technologies Strategic Research Content Security Group <Graham.Klyne@Baltimore.com> <http://www.mimesweeper.com> <http://www.baltimore.com> ------------------------------------------------------------
Received on Friday, 11 May 2001 13:28:58 UTC