These conditions can be expressed as the equality of the symmetrized Volterra kernels for two nonlinear systems which are equivalent.

这一条件可以表达为两个非线性系统的对称化渥尔特拉核相等，它构成了判定任意两个非线性系统等效的一种判据。

In 1990s based on the eigenfunction method of representation theory of groups, a new method, the symmetrized boson representation (SBR) method, was brought forward.

90年代，陈金全等人在点群的表示理论上提出了一种新的方法，对称化玻色表象方法(SBR)。