Re: The URI of a RDDL "nature"

I have raised concerns about changing the nature of XML Schema from:

http://www.w3.org/2001/XMLSchema

to (for example):

http://www.rddl.org/natures#XMLSchema

primarily because this goes the ideas that the nature of an XML  
document might be determined by the namespace of the root element.

It wasn't immediately obvious to me what the ambiguity would be using  
the namespace of XML Schema as the nature of an XML Schema resource.

After thinking about this (I don't have access to the most recent TAG  
minutes where this was discussed), I now see a problem with the  
approach http://www.rddl.org/natures/ had adopted:

Condidering the class extension of the resource http://www.w3.org/ 
2001/XMLSchema :

a) the class extension of a namespace might be considered to be the  
set of elements "in" the namespace, or the set of XML QNames "named"  
by the namespace.

b) the class extension of "XML Schema" might also be considered to be  
the set of XML Schema documents.

Therefor, if the class extension of an XML Namespace *is* considered  
to be the set of QNames, the class extension of the XML Schema  
namespace can't also be the set of possible XML Schema documents.

Consequently if we adopt the model that the RDDL nature of a resource  
determines its rdf:type, then the RDDL nature of an XML Schema  
document e.g. http://example.org/foo.xsd should not be http:// 
www.w3.org/2001/XMLSchema. That would be equivalent to asserting

	http://example.org/foo.xsd rdf:type http://www.w3.org/2001/XMLSchema

That is the same as saying that http://example.org/foo.xsd is a  
member of the XML Schema namespace ... wrong!

Note that if rddl:nature is a simple property the confict is not  
generated, i.e. there is no specific problem asserting:

	http://example.org/foo.xsd rddl:nature http://www.w3.org/2001/XMLSchema

On the other hand, if we create a new URI for the resource "the set  
of XML Schema documents" e.g. http://www.rddl.org/natures/ 
schemas#XMLSchema and we say that the nature of any individual XML  
Schema document is http://www.rddl.org/natures/schemas#XMLSchema then  
in fact making the assertion:

	http://example.org/foo.xsd rdf:type http://www.rddl.org/natures/ 
schemas#XMLSchema

would be consistent.

Comments?

Jonathan
On Jan 13, 2006, at 3:09 PM, Norman Walsh wrote:
...

>
> As you already observed, the use of "http://www.iso.ch/" as the nature
> of an ISO standard is controversial for a few reasons. The most
> technic argument against it, I think, is that it conflates "a website"
> and "a nature" so that any descriptive statement made about a nature
> must (by virtue of the use of the same URI) also be a statement about
> the website. To a greater or lesser extent, the same argument
> applies to several other nature URIs as well.
>
> ...
> http://www.w3.org/2001/XMLSchema

Received on Tuesday, 17 January 2006 23:12:37 UTC