CGAL 6.0.1  2D and 3D Linear Geometry Kernel

AdaptableUnaryFunction
CGAL::Sphere_3<Kernel>
Operations  
A model of this concept must provide:  
Kernel::Sphere_3  operator() (const Kernel::Sphere_3 &s) 
returns the sphere with the same center and squared radius as s , but with opposite orientation.  