W3C home > Mailing lists > Public > www-rdf-interest@w3.org > December 1999

Re: URIs vs URLs?

From: Dan Brickley <Daniel.Brickley@bristol.ac.uk>
Date: Mon, 13 Dec 1999 19:51:54 +0000 (GMT)
To: RDF Interest Group <www-rdf-interest@w3.org>
Message-ID: <Pine.GHP.4.21.9912131945460.3547-100000@mail.ilrt.bris.ac.uk>
On Mon, 13 Dec 1999, Jonas Liljegren wrote:

> Daniel LaLiberte wrote:
> > 
> > Jonas Liljegren writes:
> >  > Now, assuming MD5 model URIs, we would like to differ between:
> >  >
> >  >  1. The URI of the service
> >  >  2. The URL of the service
> >  >  3. The URI for the physical person
> >  >  4. The URI of the model describing the person
> >  >  5. The URL of the model describing the person
> >  >  6. The URI of the model describing the service
> >  >  7. The URL of the model describing the service
> > 
> > I'm curious what you are thinking of as the difference between URIs and
> > URLs.
> With the suggested RDF API, the model URI would be a MD5 digest, but the
> model URL would be the place there you can get it.
> To minimize confusion about what the URI denotes, the person URI should
> not be a URL leading to a document. All URIs leading to a document would
> be seen as the URI of that document, rather than the URI for something
> in "the real world".
> See the previous discussion on this:
> http://lists.w3.org/Archives/Public/www-rdf-interest/1999Dec/0055.html

I disagree. Being able to 'ask the Web' about a given URI (real world or
not) is a feature not a bug. Content and language negotiation already
ensures that that is a complex relationship between resources and the
document(s) available by talking to services associated with those
resources. The URI for the W3C logo being a classic example of
this: there is a URI for the image 'in the abstract' and two URIs for
different file formats (png and gif).

RDF is defined in terms of resources and URIs. The RDF specifications do
not invoke the URI/URL distinction, and this is for good reason. If we
want to distinguish between URI of a service and URL of a service, we
should make sure we use different URIs for those objects, and name the
relationship between the two. 

Dan (in URI advocate mode ;-)
Received on Monday, 13 December 1999 14:52:32 UTC

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