Thank you Graydon and Wolfgang. Good inputs.

For validation problems, is XPath 2.0 as powerful as XSLT 2.0?

My hunch is no, but I can't think of an example of a validation problem that
can be done in XSLT 2.0 and cannot be done in XPath 2.0. Can you think of an
example? If one could come up with an example, it would show that some
validation problems cannot be solved by Schematron and must be solved by
XSLT.

/Roger