The following terminology is used for furthest-site Voronoi diagrams in Qhull. The underlying structure is a furthest-site Delaunay triangulation from a convex hull in one higher dimension. Upper facets of the Delaunay triangulation correspond to vertices of the furthest-site Voronoi diagram. Vertices of the furthest-site Delaunay triangulation correspond to input sites. They also define regions of the furthest-site Voronoi diagram.
All vertices are extreme points of the input sites.
See qconvex conventions , furthest-site delaunay conventions , and Qhull's data structures . The last coordinate is the sum of the squares of the input site's coordinates vertex - a point on the upper facets of the paraboloid. It corresponds to a unique input site. Its coordinates are -10.101 . The same program is used for both constructions.