Uniqueness of Attributes (3)

Illegal Example :

   <!-- http://www.w3.org is bound to n1 and n2 -->
   <x xmlns:n1="http://www.w3.org" 
      xmlns:n2="http://www.w3.org" >
      <bad a="1"     a="2" />
      <bad n1:a="1"  n2:a="2" />
   </x>