Let $X : \Omega \to \mathcal{X}$ and $Y : \Omega \to \mathcal{Y}$ each be a D5723: Simple random variable.
Let $a \in (0, \infty) \setminus \{ 1 \}$ be a D5407: Positive real number.
Let $a \in (0, \infty) \setminus \{ 1 \}$ be a D5407: Positive real number.
Then
\begin{equation}
I(X ; Y)
= I(Y ; X)
\end{equation}