updated
authorChristian Urban <christian dot urban at kcl dot ac dot uk>
Mon, 22 Sep 2014 02:01:41 +0100
changeset 256 bc72478edca1
parent 255 96a99237fa42
child 257 70c307641d05
updated
hws/hw01.pdf
hws/hw01.tex
Binary file hws/hw01.pdf has changed
--- a/hws/hw01.tex	Mon Sep 22 01:57:59 2014 +0100
+++ b/hws/hw01.tex	Mon Sep 22 02:01:41 2014 +0100
@@ -48,15 +48,15 @@
 
 \item How many regular expressions are there to match the
       string $abc$? (How many if they cannot include
-      $\epsilon$ and $\varnothing$? How many if they also are
-      not allowed to contain stars? How many if they also are
+      $\epsilon$ and $\varnothing$? How many if they are also
+      not allowed to contain stars? How many if they are also
       not allowed to contain $\_ + \_$?)
 
 \item When are two regular expressions equivalent? Can you
-      think of instances where two regular expressions are
-      equivalent, but it is not so obvious that they are? For
+      think of instances where two regular expressions match
+      teh same strings, but it is not so obvious that they do? For
       example $a + b$ and $b + a$ do not count\ldots they
-      are obviously equivalent.
+      obviously match the same strings, namely $[a]$ and $[b]$.
 
 \end{enumerate}