// In header: <boost/heap/heap_concepts.hpp>
template<typename C> 
struct MergablePriorityQueue : public boost::heap::PriorityQueue< C > {
  // types
  typedef C::iterator        iterator;       
  typedef C::const_iterator  const_iterator; 
  typedef C::allocator_type  allocator_type; 
  typedef C::value_compare   value_compare;  
  typedef C::value_type      value_type;     
  typedef C::const_reference const_reference;
  // public member functions
   BOOST_CONCEPT_USAGE(MergablePriorityQueue);
   BOOST_CONCEPT_USAGE(PriorityQueue);
};