CGAL 5.1  2D Triangulation

The vertex of a triangulation included in a triangulation hierarchy has to provide some pointers to the corresponding vertices in the triangulations of the next and preceding levels. Therefore, the concept TriangulationHierarchyVertexBase_2
refines the concept TriangulationVertexBase_2
, adding handles to the corresponding vertices in the next and previous level triangulations.
CGAL::Triangulation_hierarchy_2<Tr>
Operations  
Vertex_handle  up () 
returns the corresponding vertex (if any) of the next level triangulation.  
Vertex_handle  down () 
returns the corresponding vertex of the previous level triangulation.  
void  set_up (Vertex_handle u) 
sets the handle pointing to to the corresponding vertex of the next level triangulation.  
void  set_down (Vertex_handle d) 
sets the handle pointing to the corresponding vertex of the previous level triangulation.  