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Re: Addressing the QName to URI Mapping Problem

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Tue, 21 Aug 2001 11:33:16 +0100
Message-ID: <3B8238EC.8ECB9A77@hplb.hpl.hp.com>
To: Patrick.Stickler@nokia.com
CC: www-rdf-comments@w3.org, www-rdf-interest@w3.org
Hi Patrick,

Thank you for this contribution.  A lot of careful thought has gone into it
and we are grateful.

For the momement I have listed this message under 'further discussion' of
the following issues:

http://www.w3.org/2000/03/rdf-tracking/Overview.html#rdfms-uri-substructure
http://www.w3.org/2000/03/rdf-tracking/Overview.html#rdfms-qnames-cant-represent-all-uris
http://www.w3.org/2000/03/rdf-tracking/Overview.html#rdfms-qname-uri-mapping

This will ensure that it is fully considered by the WG.

Some questions of clarification follow.

Brian


Patrick.Stickler@nokia.com wrote:

[...]
> Claim 1: An XML QName functions as a universal identifier.

It has been said that a fundamental principle of the web is that resources
are identified by URI's.

What do qnames identify?  What are the properties of these identifiers?
Where are these properties specified?  Are there examples where the same
qname identifies different things?  Can you provide examples where QName's
are used as universal identifiers.

[...]
> Claim 3: Direct suffixation of name to namespace URI can result
>          in ambiguity and therefore the integrity of knowledge
>          is not preserved.

By direct suffixation, I take it that you mean the function which turns
a qname into a URI by concatenating the URI-REF associated with the
namespace prefix with the localname part of the qname.

> 
> Claim 4: Direct suffixation of name to namespace does not preserve
>          the uniqueness of QNames and therefore is in violation of
>          required behavior defined by the XML Namespaces specification.

This one I don't quite follow.  Imagine a function TOURI which transforms
qnames to URI's.  Where in the namespaces spec does it say that all
such functions must be 1-1.  Lets take another example.  Lets say 
there is a function HASNAMESPACE which maps qnames to uri-refs.  The value
of that function is the uri-ref associated with the namespace prefix of the
qname.  Does that function contradict the namespace spec?  If it does not,
what is it that makes TOURI different?

> 
> Claim 5: Direct suffixation is not compatible with all possible URI
>          schemes and therefore introduces an unreasonable discrimination
>          against some forms of namespace URIs.

For completeness, please could you provide an example.

Thanks again

Brian
Received on Tuesday, 21 August 2001 06:36:37 GMT

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