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Re: The range of the HTTP dereference function

From: Jonathan Borden <jonathan@openhealth.org>
Date: Wed, 20 Mar 2002 00:20:24 -0500
Message-ID: <000b01c1cfce$f687ebc0$0301a8c0@ne.client2.attbi.com>
To: "Roy T. Fielding" <fielding@apache.org>, "Tim Berners-Lee" <timbl@w3.org>
Cc: <danc@w3.org>, "'www-tag'" <www-tag@w3.org>
Roy,


> > Here is my argument the HTTP URIs (without "#") should be understood as
> > referring to documents, not cars.
>
> I am more curious about how this artificial "without #" distinction came
> about.  I think it was a mistake, one of many embodied in RDF that make
> RDF incapable of reasoning about the Web.

Aside from RDFs method of creating a URIref from a QName -- which I do think
is broken -- there is no "#" distinction embodied in RDF. My view is that
URI references ought to be treated as opaque names, and as such they are
that. Why do you think that RDF is incapable of reasoning about the Web --
well perhaps RDF itself is incapable of reasoning -- but why would you think
that RDF bolstered by something like DAML +/- a rules language would be
incapable of reasoning? Surely there is no concrete alternative? Topic Maps?
In any case what is your logic?

In any case, to RDF a URIreference is just as good an opaque name as a URI.
The RDF Model Theory, for example, could care less whether a URI reference
has a '#', or any other character for that matter.

The rest of your statement I generally agree with.

[...]

Except...
>
> > In this way, Resource in URI and Resource in RDF can be similarly
anything,
> > but we have an important concept of a <part of the Web information
space>
> > <document?> or whatever.
>
> Which is false.  RDF is broken if it cannot describe the Web in its
entirety.

I am not at all sure that the idea that "http://..." URI need identify a
document is at all an RDF concept.

Rather I ask Tim how one could say _in RDF_ that "http:" scheme URIs
necessarily identify documents,  in a way that an interencing engine that
understands _only_ RDF could understand?. i.e. one is not allowed to
introduce a function "starts-with(URIref)" that RDF is expected to
understand... since RDFCore removed rdf:aboutEachPrefix, there is no such
construct, at least none I am aware of.

The bottom line is that neither the RDF or DAML (hopefully soon to be OWL)
model theories contain operators that allow one to make assertions, or
derive inferences, from parts of URI references. URI references are treated
as opaque names.

> The whole point in changing the model of the Web from a collection of
> Universal Document Identifiers that can be used to retrieve documents to
> one where Uniform Resource Identifiers are used to identify resources that
> can be accessed in the form of a representation through a uniform
interface
> was so that we could accurately model how people have been actively using
> the Web since computational hypertext was introduced in 1993.
>

Agreed.

Jonathan
Received on Tuesday, 19 March 2002 23:38:35 GMT

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