  The concept of power among players can be expressed as a combination of their
utilities. A player who obeys another takes into account the utility of the
dominant one. Technically it is a matter of superimposing some weighted sum or
product function onto the individual utility function, where the weights can be
represented through directed graphs that reflect a situation of power among the
players. It is then possible to define some global indices of the system, such
as the level of hierarchy, mutualism and freedom, and measure their effects on
game equilibria.
