Let $X, E_1, \ldots, E_N$ each be a D11: Set.

Then \begin{equation} X \setminus \bigcap_{n = 1}^N E_n = \bigcup_{n = 1}^N (X \setminus E_n) \end{equation}

Let $X, E_1, \ldots, E_N$ each be a D11: Set.

Then \begin{equation} X \setminus (E_1 \cap \cdots \cap E_N) = (X \setminus E_1) \cup \cdots \cup (X \setminus E_N) \end{equation}