<a name="boost.heap.skew_heap.implementation_defined.const_iterator"></a><span class="identifier">const_iterator</span><span class="special">;</span>     
  <span class="keyword">typedef</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span>                     <a name="boost.heap.skew_heap.implementation_defined.ordered_iterator"></a><span class="identifier">ordered_iterator</span><span class="special">;</span>   
  <span class="keyword">typedef</span> <span class="emphas