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

Re: URIs vs URLs?

From: Jonas Liljegren <jonas@paranormal.o.se>
Date: Sat, 18 Dec 1999 21:10:33 +0100
Message-ID: <385BEA39.8CF102B5@paranormal.o.se>
To: Dan Brickley <Daniel.Brickley@bristol.ac.uk>, RDF Intrest Group <www-rdf-interest@w3.org>
Dan Brickley wrote:
> 
> 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.

Well. That was what I was trying to say. That there are a URI for the
origin 
of a model and a URI for the model itself.

I did this separation for clarification. I had always imagined that the
model
URI would be the URI of its origin.


Since it is important to know if you are refering to a description of
something 
or the thing in itself, it could help the understanding to let the URI
of the
description be the description rather than the ting it describes.

http://abc/jonas could be used as the URI of the person jonas. But this
could
also be the URL of a document describing that person. If that were the
case, what
URI would you use to refer to the document, rather than the person?

-- 
/ Jonas  -  http://paranormal.o.se/perl/proj/rdf/schema_editor/
Received on Saturday, 18 December 1999 15:10:54 GMT

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