<span style='font-size:10.0pt;
font-family:Arial'>Hello,<o:p></o:p>

<span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p>

<span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>I’ve created a XML document, but it isn’t
complete, because I’ll still need to add the namespace declarations on
top when the document is ready. Therefore I’d like to use XPath to get
all prefixes, and based on that prefixes, add the namespaces. It’s not
100% correct to use fixed prefixes, I know, but it’ll solve my problem. I’ve
been trying to do something with namespace-uri() finding the unique ones, but
it didn’t work out. Can someone help me creating the right query?<o:p></o:p>

<span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p>

<span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>//*[     not(  namespace-uri() = namespace-uri(preceding-sibling::node()) 
)     ]<o:p></o:p>

<span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p>

<span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Thanks in advance,<o:p></o:p>

<span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p>

<span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Robert de Wilde<o:p></o:p>