# xy=yxx^y = y^x for integers xx and yy

We know that $2^4 = 4^2$ and $(-2)^{-4} = (-4)^{-2}$. Is there another pair of integers $x, y$ ($x\neq y$) which satisfies the equality $x^y = y^x$?

The general solution of $x^y = y^x$ is given by
It can be shown that if $x$ and $y$ are rational, then $u$ must be an integer.