ex descriptor, depending on how the adapted
edge iterator is defined. The example in
<TT>example/bellman_ford.cpp</TT> shows <TT>edge_list</TT> being used
with pointers as vertex property maps.

<P>
The reason that pointers can be used as property maps is that
there are several overloaded functions and a specialization of
<TT>property_traits</TT> in the header <a
href="../../../boost/property_map/property_map.hpp"><TT>boost/property_map/property_map.hpp</TT></a>
that implement the property map interface in 