Schemas: "Path Models" and "Axis Models"

You may be interested in a little note  "Axis Models & Path Models:
Extending DTDs with XPaths" at
http://www.ascc.net/xml/en/utf-8/validaxis.html

It looks at how XPaths could be applied to structural schemas. I identify
two possibilities:
* axis models are regular expression models that validate on different XPath
axes (an XML content model is an axis model where the axis is "children");
* path models are regular expression models in which each term is an XPath
(an XML content model is a path model where each term is a child).

Also, the note on "Weak Validation" is also updated.
http://www.ascc.net/xml/en/utf-8/weakvalid.html

Rick Jelliffe