# Green function for KG equation

1. May 14, 2010

### paweld

There exists very simple formula for Green function for wave equation:
$$G(t,x,t',x') = \delta (t-t'\pm \frac{|x-x'|}{c})/|x-x'|$$.
I wonder whether there exist similiar formula for Green function
for Klein-Gordon equation (with mass >0) for any boundary condition.

2. May 14, 2010