Kirkwood approximation

The Kirkwood superposition approximation was introduced in 1935 by John G. Kirkwood as a means of representing a discrete probability distribution. The Kirkwood approximation for a discrete probability density function P ( x 1 , x 2 , … , x n ) {displaystyle P(x_{1},x_{2},ldots ,x_{n})} is given by The Kirkwood superposition approximation was introduced in 1935 by John G. Kirkwood as a means of representing a discrete probability distribution. The Kirkwood approximation for a discrete probability density function P ( x 1 , x 2 , … , x n ) {displaystyle P(x_{1},x_{2},ldots ,x_{n})} is given by