对于整数阶常微分方程的数值解法，如欧拉法、线性多步法等都已有较完善的理论。

Numerical method of integral order ordinary differential equation, for example, Euler method, linear multiple step method, and so on, has had quite perfect theories.

youdao

本文阐述并总结了实体造型的一些理论和关键算法，如正则集理论，基于推广的欧拉公式的表示模型，集合成员分类。

Some theories and key algorithms of solid modeling such as the theory of r-sets, representation model based on generalized Euler formulas, set membership classification are explained and summarized.

youdao