[xquery-talk] Function for determining one XPath as subset of another

[Pavel Velikhov]

> On 27 Jan 2016, at 12:54, W.S. Hager <wshager at gmail.com> wrote:
> 
> Can't we formally proof something as obvious Adam's case?

In Adam’s case we want to test whether path expression p1 subsumes path expression p2.
If we don’t put any conditions on p1 and p2, the problem is undecidable: p1 and p2 may include
function calls, so the expressive power of p1 and p2 are that of a Turing Machine.