The statistical average values of some relevant operators satisfy a set of differential equations of the first order.

有关算符的统计平均值随时间的演化满足一个封闭的一阶线性微分方程组。

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And the evolution of the statistical average values of the set of operators with time satisfy a group of one-order linearly differential equations.

这组算子的统计平均值随时间的演化满足一个封闭的一阶线性微分方程组。

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Both of the observed radial velocity and separation being projective values, in order to determine the mass of binary galaxies the average projection factor may be derived by a statistical method.

双重星系或天体系统，用动力学方法测定其质量时，观测到的视向速度和距离间距，都是各自值的投影值，可用统计方法，求出一个关于它们的平均投影因子。

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