Book keeping.

src/cat/gluing/level.tex

@@ -1,7 +1,7 @@
 \section{Preimages}
 \label{section:preimage}
 
-\begin{definition}[Preimage Function]
+\begin{definition}[Preimage Function*]
 \label{definition:preimage-function}
     Let $X, Y$ be sets and $P: 2^Y \to 2^X$, then $P$ is a \textbf{preimage function} if
     \begin{enumerate}[label=(PF\arabic*)]
@@ -20,7 +20,7 @@
 \label{proposition:preimage-gymnastics}
     Let $X$ and $Y$ be sets, then:
     \begin{enumerate}
-        \item For any $f: X \to Y$, the mapping $S \mapsto f^{-1}(S)$ is a total preimage function.
+        \item For any $f: X \to Y$, the mapping $S \mapsto f^{-1}(S)$ is a total \hyperref[preimage function]{definition:preimage-function}.
         \item For any total preimage function $P: 2^Y \to 2^X$, there exists a unique $f: X \to Y$ such that $P(S) = f^{-1}(S)$ for all $S \in 2^Y$. 
     \end{enumerate}
 \end{proposition}