> To be both in the xhtml namespace *and* be DTD valid, it follows that 
> the namespace must use the default xmlns.

well not really, the XHTML DTD goes to extraordinary lengths to allow
prefixes to be specified, by setting a parameter entity in the local
subset or elsewhere, (which means that the dtd never refers to an
element name directly, always via a parameter entity) a document that
uses prefixes after setting the appropriate entities may well be dtd
valid. All XHTML rendering agents will render prefixed XHTML. The XHTML
spec does then have this bizare conformance clause that says that
despite all the technical effort in the specification of the DTD and in
implementations to allow prefixes, a document dhouldn't use them, but I
don't understand that clause s tend to ignore it:-)

of course the whatwg inspired html5 proposals take another approach
altogether and just define the language in the text, and via a parsing
algorithm, with no dtd or schema at all.

David



________________________________________________________________________
The Numerical Algorithms Group Ltd is a company registered in England
and Wales with company number 1249803. The registered office is:
Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom.

This e-mail has been scanned for all viruses by Star. The service is
powered by MessageLabs. 
________________________________________________________________________