Added the Mackey-Arens theorem.

src/dg/complex/space.tex

@@ -24,8 +24,8 @@
 
     and the following are equivalent:
     \begin{enumerate}[label=(C\arabic*)]
-        \item $\cf$ is precompact in $H(U; E)$. 
-        \item $\cf$ is bounded in $H(U; E)$, and for each $x \in U$, $\cf(x) = \bracs{f(x)|f \in \cf}$ is precompact.  
+        \item $\cf$ is relatively compact in $H(U; E)$. 
+        \item $\cf$ is bounded in $H(U; E)$, and for each $x \in U$, $\cf(x) = \bracs{f(x)|f \in \cf}$ is relatively compact.  
     \end{enumerate}
 \end{theorem}
 \begin{proof}