--- a/hws/hw02.tex	Thu Sep 26 10:52:54 2013 +0100
+++ b/hws/hw02.tex	Thu Sep 26 11:05:54 2013 +0100
@@ -9,6 +9,12 @@
 \section*{Homework 2}
 
 \begin{enumerate}
+\item What is the meaning of a regular expression? Give an inductive definition.
+
+\item Given the regular expressions $r_1 = \epsilon$ and $r_2 = \varnothing$ and $r_3 = a$.
+How many strings can the regular expressions $r_1^*$, $r_2^*$ and $r_3^*$ each match?
+
+
 \item Give regular expressions for (a) decimal numbers and for (b) binary numbers. 
 (Hint: Observe that the empty string is not a number. Also observe that leading 0s 
 are normally not written.)