There are a lot of NP-hard optimization problems in the engineering application, which are difficult to solve by traditional mathematical techniques.

在实际工程应用中有很多优化问题是NP难问题，难以应用传统数学方法来解决。

Multiobjective optimization is a useful mathematical model in many areas, such as economics, engineering, and decision making, to solve real world problems with conflicting objectives.

对于经济、工程、决策等领域中带有冲突目标的实际问题，多目标优化是一个有用的数学模型。

Complementarity problems are of an important branch in the mathematical programming field, which are widely found in many fields such as engineering, economics and traffic control.

互补问题是一类非常重要的优化问题，它在工程，经济与交通平衡等领域有着广泛的应用。