Fig. 2

The standard Voronoi cell, Voronoi S cell and radical Voronoi cell of circle E in 2D space. The boundaries of standard Voronoi cell (purple lines) and radical Voronoi cell (green lines) are straight line, but the boundary of Voronoi S cell (blue lines) is a hyperbolic curve. In the local environment formed by circle C, D and E, the center of local largest void coincides with O_S, and the deviation of O_R from O_S is less than the deviation of O_V from O_S.