Thank you Michael

this makes complete sense. Indeed my question is a first order problem.

Always
Leo


> On 15.04.2012, at 18:34, Michael Kay wrote:
>
> XPath 1.0 is not "relationally complete", that is, there are queries
expressible in first-order predicate calculus that are not expressible in
XPath 1.0. This might well be one of them. In such cases you need some
assistance from the host language (e.g. XSLT or Java).
>
> Michael Kay
> Saxonica