Let $f : X \to Y$ be a D18: Map such that
(i) | \begin{equation} E \subseteq F \subseteq Y \end{equation} |
Then
\begin{equation}
f^{-1}(E)
\subseteq f^{-1}(F)
\end{equation}
(i) | \begin{equation} E \subseteq F \subseteq Y \end{equation} |