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The URI dereferencing rathole was: Re: proposal to close Issue 5.8 Datatypes

From: Jonathan Borden <jonathan@openhealth.org>
Date: Wed, 27 Nov 2002 08:00:35 -0500
Message-ID: <019201c29614$fae7e910$7c674544@ne.mediaone.net>
To: <connolly@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: <www-webont-wg@w3.org>

Peter F. Patel-Schneider wrote:

>
> From: Dan Connolly <connolly@w3.org>
> Subject: Re: proposal to close Issue 5.8 Datatypes
> Date: 25 Nov 2002 17:13:00 -0600
>
> [...]
>
> > > Huh?  Are not XML Schema documents WWW documents?  Do not all WWW
documents
> > > have URIs?
> >
> > Hmm... well, with a certain reading of the specs (the
> > 'connected XML document' reading discussed in
> > http://www.w3.org/2000/06/uriqa3934.html ), each XML document
> > has a URI; and XML Schema documents are XML documents.
> >
> > But it's entirely possible to have two XML Schema documents
> > with the same URI, and that that associate different types with
> > the same name. I suppose we could treat that
> > in the usual "doctor, it hurts when I do that" manner,
> > but I'm still uneasy about how to specify this.
>
> I'm confused.  What is the thing that is used to reference a document on
> the WWW?  Isn't this a URI?  Is it possible to have two different RDF
> documents with the same URI?  Could these two different documents make
> entirely different statements?
>

This is similar to the owl:imports issue. There are a few issues in formally
stating that making a particular assertion about a URI entails the
'contents' of the document found at the URI. One of the issues (for
instance) is content negotiation:

A web server can be configured to serve *different* documents depending on
HTTP request headers e.g. each of:

Accept: appliction/rdf+xml
Accept: application/xml
Accept: text/html

may result in an entirely different HTTP response message.
Similar problems might exist for servers that 'switch' off of other request
headers, user identification, as a function of time, etc.

I suppose we could formally define a canonical HTTP request, my next message
contains a short description of a way to easily do this.

Jonathan
Received on Wednesday, 27 November 2002 08:20:50 GMT

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