Let $X_n$ be a D11: Set for each $n \in \mathbb{N}$.
Let $\pi : \mathbb{N} \to \mathbb{N}$ be a D353: Set automorphism on $\mathbb{N}$.
Let $\pi : \mathbb{N} \to \mathbb{N}$ be a D353: Set automorphism on $\mathbb{N}$.
Then
\begin{equation}
\bigcup_{n \in \mathbb{N}} X_n = \bigcup_{n \in \mathbb{N}} X_{\pi(n)}
\end{equation}