Comment on DITA 1.1: Defining and using normative URIs for all DITA-Supplied Schema Components

[EricS, Eliot, and I have been discussing this topic that
I am now putting forward as a comment on DITA 1.1.  paul]

All the DITA 1.1 DTD modules have official formal public
identifiers that are used to reference them.  For example,
topic.dtd references programmingDomain.ent via:

%pr-d-dec;

The public identifier can be used in a catalog to point to
wherever the desired module may really be.

However, the DITA 1.1 XSDs do not parallel this situation.
We have only defined URIs for the top level shells, and the
XSDs have xs:includes that refer directly to modules; e.g.,
topic.xsd references programmingDomain.xsd via: