Houjun Liu

stationary-action principle

The stationary-action principle states that, in a dynamic system, the equations of motion of that system is yielded as the “stationary points” of the system’s action. i.e. the points of “least” action. (i.e. a ball sliding down a ramp is nice, but you don’t expect it—in that system—to fly off the ramp, do a turn, and then fly down.