Describing the "nature" of a resource

At the last TAG f2f, we discussed namespaceDocument-8. We're going to
do it again at our next f2f and I'd really like to make progress.

As I understood discussion[1] at our last f2f, one of the most
significant issues with our current draft[2] was raised by Dan. Dan
expressed skepticism over the way we'd proposed to model natures.

(Note that we've introduced a conceptual model that doesn't have to bear
a 1:1 correspondence with any particular RDDL syntax so this discussion
is, at least for the moment, about the model and not the particular URIs
used by RDDL.)

The current draft says that natures have URIs and we identify the nature
of a resource with those URIs.

For example:

<http://docbook.org/xml/5.0b1/rng/docbook.rng>
   assoc:nature <http://relaxng.org/ns/structure/1.0> .

asserts that the nature of the docbook.rng file is a RELAX NG grammar.

The concern raised was that such a statement is a statement of opinion
and not of fact. This is even easier to see in cases like HTML 4 where
we assert the nature of a resource by pointing to its normative
specification. It's not hard to imagine the existence of formats for
which the normative specification is *clearly* a matter of opinion.

Dan suggested instead that we should ground natures in fact. For
example,

<http://docbook.org/xml/5.0b1/rng/docbook.rng>
   xxx:docRootEltName ("http://relaxng.org/ns/structure/1.0" "grammar") .

This "docRootEltName" property points to a list which identifies the
namespace name and local name of the root element. This clearly is a
matter of fact, not opinion.

Personally, I'm just as happy with assertions in this case, but I did
agree to attempt to find facts we could use. I've taken the current list
of natures and considered how we might ground them in fact:

CSS                     content-type    text/css
DTD                     content-type    application/xml-dtd
Mailbox                 ???
Generic HTML            content-type    text/html
HTML 4                  ???
HTML 4 Strict           ???
HTML 4 Transitional     ???
HTML 4 Frameset         ???
XHTML                   docRootEltName  xhtml:html
XHTML 1.0 Strict        ???
XHTML 1.0 Transitional  ???
RDF Schema              ???
RELAX NG Schema (RNC)   content-type    application/relax-ng-compact-syntax
RELAX NG Schema         docRootEltName  rng:grammar
Schematron Schema       ???
OASIS Open Catalog      ???
XML Catalog             docRootEltName  cat:catalog
XML Scheam              docRootEltName  xs:schema
XML Character Data      ???
XML Escaped             ???
XML Unparsed Entity     ???
IETF RFC                ???
ISO Standard            ???

For some, we can rely on the content-type, I think. And for others, the
document root element name. But for many, I don't see an obvious answer
and so I'm not sure how to proceed.

Suggestions most welcome.

                                        Be seeing you,
                                          norm

[1] http://www.w3.org/2001/tag/2007/03/07-morning-minutes
[2] http://www.w3.org/2001/tag/doc/nsDocuments/
-- 
Norman Walsh <ndw@nwalsh.com> | The perfect man has no method; or
http://nwalsh.com/            | rather the best of methods, which is
                              | the method of no-method.-- Shih-T'ao