| (1) | $X$ is a D11: Set |
| (2) | \begin{equation} \mathcal{E} \subseteq \{ E \subseteq X : |E| = 2 \} \end{equation} |
| (1) | $X$ is a D11: Set |
| (2) | \begin{equation} \mathcal{E} \subseteq \{ E \subseteq X : |E| = 2 \} \end{equation} |
| (1) | $X$ is a D11: Set |
| (2) | \begin{equation} \mathcal{E} \subseteq \mathcal{P}_2(X) \end{equation} |