If the gauge compensating term is added to the action, the S matrix in the physical state vector space can be expressed in a form which has no couplings of physical and unphysical particles, and so the physical S matrix is gauge independent and unitary.

• 在作用量中添上规范补偿项以后；物理态空间中的S矩阵可以写成物理粒子和非物理粒子之间没有耦合的形式；显示出S矩阵的规范无关性和么正性.