underlying variables meaning in English

基础变量

Which means the procedure cannot change the underlying variable element
，这意味着过程无法更改基础变量元素。
Specifies that the procedure can modify the underlying variable element in the calling code the same way the calling code itself can
指定过程可以用与调用代码本身所用的相同方式修改调用代码中的基础变量元素。
There have been at least two approaches to amend this problem : either by combining several variables to form a more complex model , or by trying to identify underlying variables , the reasons for which size , technology and environment seem to cause structural differences
这个问题有两种方式来解决：一是将几个变量组合成一个更加复杂的模型；二是试图寻找隐藏的变量，即导致上述因素影响结构差异的原因。
For the american put option which does not have analytical solution , several new numerical algorithms are presented on its pricing , each of them is given finite difference method and finite element method on variables based on individual underlying variable and two underlying variable respectively . for finite element method , bilinear interpolation of rectangular sectioning is adopted
另外，对不存在解析解的美式看跌期权的定价给出了几种新的数值算法，分别对基于单个标的变量和两个标的变量的美式看跌期权定价给出了有限差分法和有限元法，有限元法采用了矩形剖分的双线性插值。