## TriangulationHierarchyVertexBase_2

### Definition

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 preceeding levels. Therefore, the concept TriangulationHierarchyVertexBase_2 refines the concept TriangulationVertexBase_2, adding handles to the correponding vertices in the next and previous level triangulations.

### Refines

TriangulationVertexBase_2

### Operations

Vertex_handle | v.up () | returns the corresponding vertex (if any) of the next level triangulation;
Vertex_handle | v.down () | returns the corresponding vertex of the previous level triangulation;
void | v.set_up ( Vertex_handle u)
|  | sets the handle pointing to to the corresponding vertex of the next level triangulation;
void | v.set_down ( Vertex_handle d)
|  | sets the handle pointing to the corresponding vertex of the previous level triangulation;

### Has Models

CGAL::Triangulation_hierarchy_vertex_base_2<Vb>

### See Also

Triangulation_hierarchy_2<Tr>