- From: Thomas B. Passin <tpassin@comcast.net>
- Date: Wed, 23 Jun 2004 19:20:59 -0400
- To: "www-rdf-interest@w3.org" <www-rdf-interest@w3.org>
Jon Hanna wrote: > I read that as good separation between specs. > > 1. URIs provide a way to identify resources. > 2. HTTP provides a way to GET or PUT representations of resources, or POST > represetations into them. > 3. RDF provides a way to describe relationships between resources identified by > URIs, or between resources and literals. Well, 1) and 3) go together nicely. It's just 2) that is the odd man out. A lot of people would like to have a retrievable URI denote the thing that gets retrieved, or at least the resource of which the retrieved thing is a representation. Trouble is, it leads to so many problems that no one has convinced many others that they know how to make it work. For example, given a retrievable URI - A. Does it denote i) the URI string itself, ii) the resource whose representation gets retrieved, or iii) one of the representations (and if so, which one?)? B. If you picked ii) or iii), how do you talk about the URI string itself? C. How do you know which URIs are supposed to be treated one way - as denoting the resource they point to - and which the other, given that actual sites go up and down, change, domains get bought and sold, etc.? D. If you picked A.ii or A.iii, what is supposed to happen when the resource itself changes its state, which may mean gets completely changed or replaced? These are not trivial questions to answer. Maybe we will eventually get a convergence on a solid and reliable convention about the issue, but until we do, what can we do except to go along with what the current RDF Rec(s) say? > That HTTP, RDF and indeed RDS don't have anything to say about each other is > dulce et decorum; but they both depend on the use of URIs to identify resources > and when a URI is used in both HTTP and RDF then it sould identify the same > resource (or it's a pretty lousy identifier, not an identifier at all really). > &rdf;type and &rdfs;label seem like pretty good identifiers to me, and they don't have to be retrievable - and if they were, they would not denote the retrieved thing. Cheers, Tom P -- Thomas B. Passin Explorer's Guide to the Semantic Web (Manning Books) http://www.manning.com/catalog/view.php?book=passin
Received on Wednesday, 23 June 2004 19:18:33 UTC