1  <XPath xmlns:ietf="http://www.ietf.org" >
 2      (//.|//@*|//namespace::*)
 3      [
 4  	self::ietf:e1
 5  	    or
 6  	(parent::ietf:e1 and not(self::text() or self::e2))
 7  	    or
 8  	count(id("E3")|ancestor-or-self::node()) = count(ancestor-or-self::node())
 9      ]
10  </XPath>