--- a/slides/slides10.tex	Tue Dec 02 12:27:12 2014 +0000
+++ b/slides/slides10.tex	Tue Dec 02 22:33:23 2014 +0000
@@ -343,7 +343,7 @@
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[t]
-\frametitle{\begin{tabular}{c}4rd Lecture:\\ Unix Access Control\end{tabular}}
+\frametitle{\begin{tabular}{c}4th Lecture:\\ Unix Access Control\end{tabular}}
 
 \begin{itemize}
 \item privileges are specified by file access permissions (``everything is a file'') 
@@ -379,7 +379,7 @@
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[fragile,t]
-\frametitle{\begin{tabular}{c}4rd Lecture:\\ Unix Access Control\end{tabular}}
+\frametitle{\begin{tabular}{c}4th Lecture:\\ Unix Access Control\end{tabular}}
 
 \begin{itemize}
 \item when a file with setuid is executed, the resulting process will assume the 
@@ -406,7 +406,7 @@
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[t]
-\frametitle{\begin{tabular}{c}4rd Lecture:\\ Unix Access Control\end{tabular}}
+\frametitle{\begin{tabular}{c}4th Lecture:\\ Unix Access Control\end{tabular}}
 
 \begin{itemize}
 \item Alice wants to have her files readable,