>iterator_property_map</tt></a>
constructed from a <tt>std::vector</tt> of graph 2's vertex
descriptor type and the vertex index map for graph 1.<br>
<b>Python</b>: Must be a <tt>vertex_vertex_map</tt> for the first graph.
</blockquote>

IN: <tt>vertex_invariant1(VertexInvariant1 i1)</tt>
IN: <tt>vertex_invariant2(VertexInvariant2 i2)</tt>
<blockquote>
Mappings from vertices to integers which restrict which vertices may be
considered isomorphic. If a candidate isomorphism maps <i>v1</i> to <i>v2</i>
but <i>