XPath and XSD/RNG

Is there a way to check whether an XPath expression could possibly be  
true for a document conforming to a particular W3C XML Schema (or  
Relax NG schema) without having access to the document? Is this  
something that toolkits support?

E.g. if the schema disallows /root/element/subelement, the XPath  
expression /root/element/subelement[0] cannot yield a non-null result  
for any conforming document.

Thanks,
Stefan

--
Stefan Tilkov, , http://www.innoq.com
innoQ Deutschland GmbH, Halskestr. 17, D-40880 Ratingen, Germany
Phone: +49 170 471 2624  Fax: +49 2102 77160-1
ICQ: 177869128, AIM: stefantilkov, Weblog: http://www.innoq.com/blog/st/