I would like to know what is the latex command to include a double lower index using sigma notation (i.e: second index lies underneath the first index)?

I tried typing:

\displaystyle\sum_{m,n=-\infty, \; (m,n)\neq (0,0)}^{\infty}
\left[
  \frac{1}{(z-2 m\omega_{1} - 2 n\omega_{2})^{2}}
 -\frac{1}{   4(m\omega_{1} +   n\omega_{2})^{2}}
\right] 


I would appreciate the assistance. Thanks


Question: Java and JVM license
Answer: Well, as I understand it, you can implement the specification all you like - to be able to legitimately call it "Java" you have to license and pass the compatibility kit, which apparently isn't trivial.

Android is not "java" although it uses the java language. It doesn't even attempt to pass the TCK.