Fix typo "earlier rather than later"

background/background.tex

@@ -306,7 +306,7 @@ \subsection{Asserts}
 Here is a quick example with an assert.
 Let's say that we are writing code using memcpy.
 We would want to put an assert before that checks whether my two memory regions overlap.
-If they do overlap, memcpy runs into undefined behavior, so we want to catch that problem than later.
+If they do overlap, memcpy runs into undefined behavior, so we want to catch that problem earlier rather than later.
 
 \begin{lstlisting}[language=C]
 assert(!(src < dest+n && dest < src+n)); //Checks overlap