diff -r 96114cc02150 -r c41b68818eae hws/hw02.tex
--- a/hws/hw02.tex	Tue Dec 04 00:33:26 2018 +0000
+++ b/hws/hw02.tex	Sat Dec 29 10:30:27 2018 +0000
@@ -35,9 +35,10 @@
       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
+      (b) binary numbers. Hint: Observe that the empty string
       is not a number. Also observe that leading 0s are
-      normally not written.)
+      normally not written---for example the JSON format for numbers
+      explicitly forbids this.
 
 \item Decide whether the following two regular expressions are
       equivalent $(\ONE + a)^* \equiv^? a^*$ and $(a \cdot