Let $E_j$ be a D11: Set for each $j \in J$ such that
(i) | $\bigcup_{j \in J} E_j$ is a D77: Set union for $\{ E_j \}_{j \in J}$ |
Then
\begin{equation}
\forall \, i \in J :
E_i
\subseteq \bigcup_{j \in J} E_j
\end{equation}