In general, if a system of differential equations has a sufficiently rich set of first integrals such that its solutions can be expressed by these integrals, then we call the system is integrable.

• 一般说来，一个常微分方程动力系统称为是可积的，如果它有足够多的首次积分使得它的所有解都可以由这些首次积分函数表示。