Let $E_n$ be a D11: Set for each $n \in \mathbb{N}$ such that

(i)	$\bigcup_{n \in \mathbb{N}} E_n$ is a D77: Set union for $\{ E_n \}_{n \in \mathbb{N}}$

Then \begin{equation} \forall \, k \in \mathbb{N} : E_k \subseteq \bigcup_{n \in \mathbb{N}} E_n \end{equation}

Let $E_n$ be a D11: Set for each $n \in \mathbb{N}$ such that

(i)	$\bigcup_{n \in \mathbb{N}} E_n$ is a D77: Set union for $\{ E_n \}_{n \in \mathbb{N}}$

Then \begin{equation} E_1 \subseteq \bigcup_{n \in \mathbb{N}} E_n, \quad E_2 \subseteq \bigcup_{n \in \mathbb{N}} E_n, \quad E_3 \subseteq \bigcup_{n \in \mathbb{N}} E_n, \quad \ldots \end{equation}