point approximation

Based on the thermodynamic model of ideal gas of cosmic strings, the string tension is calculated by the saddle point approximation and the expression of string tension is obtained.

由宇宙弦的理想气体热力学模型出发，用鞍点近似方法，导出了宇宙弦的弦张力表达式。

For all the terms of point, straight line, parallel line, real number, equality, function, derivative and so on, we must put forward three different terms of ideal, approximate and omnipotent approximation.

对于点、直线、平行线、实数、相等、导数、函数等基本数学名词，都应当提出近似、全能近似、理想三类不同的术语。

Isolate Point of Operator Essential Spectrum in the Approximation for Bounded Linear Operator

有界线性算子逼近问题中算子本质谱孤立点的处理

Taking advantage of the spherical trigonometry and a higher order approximation, the horizontal coordinates of the position for the midpoint and the departure point of the trajectory can be calculated directly in the spherical polar coordinates.

轨迹中点和起始点水平坐标的求得可以利用球面三角，直接在球极坐标中进行，并采用一些较高的近似。