equilibrium

Equilibrium is a state where all forces are equal, or in a robotic or agent system, when no further rules fire, so that there is no further change. This may persist for ever, but if the situation changes or there are external events or actions, the state may non longer be in equilibrium. Positions of equilibrium may be stable, when small changes mean that the system does not change, or changes very little, For example, a heavy concrete block would need a lot of force to tip over. Other systems are in unstable equilibrium, for example, a pole carefully balanced. A related concept to equilibrium is homeostasis, the tendency of sume systems to try to constantly move towards near equilibrium.