- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Sun, 22 Jul 2007 17:38:52 +0200
- To: "Mark Baker" <distobj@acm.org>
- Cc: "Chris Bizer" <chris@bizer.de>, www-tag@w3.org, semantic-web@w3.org, "Linking Open Data" <linking-open-data@simile.mit.edu>
On 22 Jul 2007, at 14:37, Mark Baker wrote: > On 7/7/07, Chris Bizer <chris@bizer.de> wrote: >> 1. DBpedia: http://dbpedia.org/resource/Tim_Berners-Lee >> 2. Hannover DBLP Server: >> http://dblp.l3s.de/d2r/resource/authors/Tim_Berners-Lee >> 3. Berlin DBLP Server: >> http://www4.wiwiss.fu-berlin.de/dblp/resource/person/100007 >> 4. RDF Book Mashup: >> http://www4.wiwiss.fu-berlin.de/bookmashup/persons/Tim+Berners-Lee [...] > IMO, those URIs identify different resources. I say this because they > all return different representations when I dereference them. You forget that there's a 303 redirect in each of these cases. In other words, the representations you see are representations of *other*, related, information resources. They are *not* representations of the resources identified by those URIs. Quote Roy's proposed new description for 303 See Other [1]: | A 303 response to a GET request indicates that the requested resource | does not have a representation of its own that can be transferred by | the server over HTTP. The Location URI indicates a resource that is | descriptive of the requested resource such that the follow-on | representation may be useful without implying that that it adequately | represents the previously requested resource. Note that answers to the | questions of what can be represented, what representations are adequate, | and what might be a useful description are outside the scope of HTTP and | thus entirely determined by the resource owner(s). In other words: We don't know if the resources above have any representations. Thus, your conclusion that they must be different resources is unfounded. Yours, Richard [1] http://www.w3.org/Protocols/HTTP/1.1/rfc2616bis/issues/#i70 > If they > identified the same resource then their representations would be > identical (see Roy's definition of resource in his REST dissertation). > > The tricky bit here is to remember to account for agency; to recognize > that although dbpedia.org uses URI #1 to identify Tim, from a third > party's POV it identifies dbpedia.org's *view* of Tim. > >> Question 3: Depending on the answer to question 1, is it correct >> to use >> owl:sameAs [6] to state that http://www.w3.org/People/Berners-Lee/ >> card#i and >> http://dbpedia.org/resource/Tim_Berners-Lee refer to the same >> thing as it is >> done in Tim's profile. > > No. AIUI, owl:sameAs is a very strong predicate which declares > subject and object to be the same resource. I only foresee it being > used by a publisher to declare equivalence of their own URIs, because > being able to guarantee equivalence requires a very tight degree of > control over them (i.e. be able to serve identical representations for > all time). > > Mark. > -- > Mark Baker. Ottawa, Ontario, CANADA. http://www.markbaker.ca > Coactus; Web-inspired integration strategies http://www.coactus.com > >
Received on Sunday, 22 July 2007 15:39:10 UTC