Let $X_j$ be a D11: Set for each $j \in J$ such that

(i)	$\bigcup_{j \in \emptyset} X_j$ is the D77: Set union of $X = \{ X_j \}_{j \in \emptyset}$

Then \begin{equation} \bigcup_{j \in \emptyset} X_j = \emptyset \end{equation}