Stability of the Cauchy distribution
= Stability of the Cauchy distribution
If $X_1,\ldots,X_n$ are independent standard Cauchy random variables, then
$$
\frac{X_1+\cdots+X_n}{n}
$$
is again standard Cauchy. Indeed, its characteristic function is $(e^{-|t|/n})^n=e^{-|t|}$.