- From: Booth, David (HP Software - Boston) <dbooth@hp.com>
- Date: Fri, 3 Feb 2006 23:57:52 -0500
- To: "Ben Adida" <ben@mit.edu>
- Cc: "Dan Connolly" <connolly@w3.org>, "Jeremy Carroll" <jjc@hpl.hp.com>, "Miles, AJ (Alistair)" <A.J.Miles@rl.ac.uk>, "SWBPD list" <public-swbp-wg@w3.org>, "public-rdf-in-xhtml task force" <public-rdf-in-xhtml-tf@w3.org>, "Pat Hayes" <phayes@ihmc.us>
Cut to the chase: My best guess at this point is that the practice of having http://www.w3.org/People/Connolly/#me identify both a location within a document *and* a foaf:Person is NOT actually in conflict with the WebArch, although the WebArch is confusing in this area. Full explanation below. > From: Ben Adida [mailto:ben@mit.edu] > . . . > Now I'm very confused. > > I thought we were discussing whether a resource that *might* be an > HTML document *could* also be a non-information resource, say a > person. Let's take a precise example. > > DanC's FOAF Person URI is <http://www.w3.org/People/Connolly/#me>, > but <http://www.w3.org/People/Connolly/> returns HTML, which makes > <http://www.w3.org/People/Connolly/#me> a (potential) HTML element. The httpRange-14 decision says that if an HTTP GET of http://www.w3.org/People/Connolly/ returns a 2xx status, then http://www.w3.org/People/Connolly/ is an "information resource". The WebArch says that the meaning of the fragment identifier ("#me") is determined by the media type that is returned. In the case of HTML, it identifies a location with the HTML document. Therefore, according to the WebArch plus the httpRange-14 decision, http://www.w3.org/People/Connolly/#me identifies a location within an HTML document. If Dan is also using http://www.w3.org/People/Connolly/#me to identify a foaf:Person, then the same URI is being used both to identify a foaf:Person and an "information resource". Is this okay? Pat Hayes does not see this as a problem, as he has eloquently explained. However, the WebArch says that a URI should only identify one resource, so my issue was this behavior seemed inconsistent with the WebArch. On the other hand, the WebArch also says that if multiple media types are served using content negotiation, then because the meaning of the fragment identifier could differ for different media types, the URI owner should ensure that all such meanings are "sufficiently consistent"[1] (and hence conceptually would still only identify a single resource). The WebArch also says that "The representation provider decides when definitions of fragment identifier semantics are are sufficiently consistent". Is it reasonable to think that the use of http://www.w3.org/People/Connolly/#me as a location within a document would be "sufficiently consistent" with its use as a foaf:Person? I would not have thought so, since, to me, a document seems very different from a person. In fact, I could well imagine the class of tag:Location-Within-An-HTML-Document as being owl:disjointWith foaf:Person. However, as Jeremy pointed out, there clearly is an intentional relationship between them: the location within the HTML document provides a human-readable description of the same foaf:Person. I.e., in some sense, a coercion is possible between them. If this is the kind of "consistency" that the TAG intended, then my concern about this practice conflicting with the WebArch is unfounded. Also, I just ran across some of TimBL's earlier thoughts[2] on the TAG's RDFinXHTML-35 issue[3], and they give further evidence that this *is* the kind of "consistency" that the TAG intended. So my best guess at this point is that the practice of having http://www.w3.org/People/Connolly/#me identify both a location within a document *and* a foaf:Person is NOT actually in conflict with the WebArch, although the WebArch is confusing in this area. > > DBooth, I thought you were saying that this is probably a bad thing, > assuming HTMLElement subclasses InformationResource, etc... > > Did I misunderstand? Answered above. > > If DanC's setup is okay by the TAG, then I *think* that means that a > secondary resource can be a non-information resource, even when its > primary resource is an information resource. Someone correct me if > I've lost it. That is definitely true. I don't think the debate was ever about that. However, it depends on the *media* *type* that is returned -- not merely on the fact that the primary resource is an information resource. Ben, thanks for all your work on this. It's a very nice primer. David Booth [1] WebArch on fragment identifiers and content negotiation: http://www.w3.org/TR/webarch/#frag-coneg [2] TimBL thoughts on RDF in HTML: http://www.w3.org/2002/04/htmlrdf [3] TAG issue RDFinXHTML-35: http://www.w3.org/2001/tag/issues.html#RDFinXHTML-35 [4] RDF/A Primer: http://www.w3.org/2001/sw/BestPractices/HTML/2006-01-24-rdfa-primer [5] Alistair's issues on URI usage in RDF/A primer: http://lists.w3.org/Archives/Public/public-swbp-wg/2006Jan/0113.html
Received on Saturday, 4 February 2006 04:58:02 UTC