Zone and double zone diagrams in abstract spaces
Daniel Reem, Simeon Reich · Colloquium Mathematicum · 2009
A zone diagram of order $n$ is a relatively new concept which was first defined and studied by T. Asano, J. Matou\v{s}ek and T. Tokuyama. It can be interpreted as a state of equilibrium between $n$ mutually hostile kingdoms. Formally, it is a fixed point