<doc xmlns:ietf="http://www.ietf.org" xmlns="http://www.ietf.org" xmlns:w3c="http://www.w3.org">
    <e1>
        <e2 xmlns="">
            <e3 id="E3"/>
        </e2>
	</e1>
<!--(//. | //@* | //namespace::*)[self::e1 or (parent::e1 and not(self::text() or self::e2)) or count(id("E3")|ancestor-or-self::node()) = count(ancestor-or-self::node())]-->
</doc>