We have already stated that our main concern will be the study of systems for which linear, time-invariantdifferential equations provide a useful model.
前已指出：我们主要关心的是用线性、时不变微分方程作为实用的模型系统。
2
The differential invariants are robust to the noise and also invariant to the translation and rotation.
微分不变量具有平移和旋转不变性，并且对噪声具有较强的鲁棒性。
3
Abstract: Some problems of quantum mechanics can be solved easily by means of the invariant of differential equation.