- From: Sean B. Palmer <sean@mysterylights.com>
- Date: Sun, 26 Aug 2001 15:38:08 +0100
- To: "Larry Masinter - LMM@acm.org" <lmnet@attglobal.net>, "Aaron Swartz" <aswartz@upclink.com>, "Al Gilman" <asgilman@iamdigex.net>
- Cc: <uri@w3.org>
> The tdb form would certainly appear to be useful in > creating the sort of URIs one needs for the "predicate" > URI in an RDF (subject, predicate, object) triple. It > fits the 'test case' reference in EARL to a T, [...] And I had to redraft that particular part of the EARL schema in order to cope with the fact that people were bound to try to embed the contextual information (date or version) within an identifier itself. I simply defined a sub class of resources which are date and version-less :-) Note that earl:TestCase is generally an Object/Class, not a Predicate/Property value. Properties can be Objects too, of course. [...] > If this violates a semantic assumption of URNs, The semantic assumptions for URNs are the same as those for any URI. Persistence within a given context. The "urn:" parts simply adds an informative "organizational commitment to persistent", which may or may not be helpful to humans, and is never helpful to machines. > then the tdb form should be a new root scheme which > may take an URL or URN (encoded as required) > including a duri as its 'by' argument. It could be a new root URI scheme, in that any URN scheme can be a URI scheme and vice versa. Consider the ISBN scheme. Roy Fielding argued that because ISBN schemes are reused, they cannot be URNs, but can be URIs. Of course, they *can* be URNs because the persistence of an ISBN identifer is good enough to be used... an ISBN identifier persistently identifies the book that most commonly has that identifier printed on it somewhere. It is the identifier of a currently published book using that identifier. Similarly, URLs can be looked upon as URNs... the URL http://www.w3.org/index persistently identifes the resource "index" on the www.w3.org server. The persistence of an identifer always depends upon the scope in which it is being used, and if you go to a very abstract level, then you get persistence such that the identifier would qualify as a URN. But URN doesn't give a quantitative figure for that, and IMO that's broken. -- Kindest Regards, Sean B. Palmer @prefix : <http://webns.net/roughterms/> . :Sean :hasHomepage <http://purl.org/net/sbp/> .
Received on Sunday, 26 August 2001 10:38:18 UTC