In Sato's theory, the following formal delta function is defined: $\delta(\lambda,z)=\frac{1}{\lambda}\sum_{n=-\infty}^\infty(\frac{z}{\lambda})^n=\frac{1}{z}\frac{1}{1-\lambda/z}+\frac{1}{\lambda}\frac{1}{1-z/\lambda}$ Given a function $f(z)=\sum a_iz^i$, $f(\lambda)\delta(\lambda,z)=f(z)\delta(\lambda,z)$. I want to know the properties as many as possible. Or useful references are welcome to be provided. Thanks!