Principle of stationary action

The principle of stationary action for the Action (physics) S (a measure of the energy of the system under study) states that the variation in S is at an extremum, in symbols:

Related Topics:
Action (physics) - Energy - Variation in S

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:rac{delta S}{delta x_{i}(t)}=0

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where the independent variables are denoted by a set of x_{i}(t) acting at some time t.

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See: Action (physics) #Euler-Lagrange equations for the action integral for the conditions when this principle is true.

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Extremum can in fact mean a local minimum, a local maximum, or a stationary value.

Related Topics:
Local minimum - Local maximum - Stationary value

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