--- a/Journal/Paper.thy Fri Nov 11 23:38:10 2011 +0000
+++ b/Journal/Paper.thy Sun Nov 20 22:53:50 2011 +0000
@@ -413,7 +413,7 @@
\end{dfntn}
\noindent
- And then `forget' automata.
+ And then `forget' automata completely.
The reason is that regular expressions, unlike graphs, matrices and
functions, can be easily defined as an inductive datatype. A reasoning
infrastructure (like induction and recursion) comes for free in
@@ -2114,9 +2114,9 @@
@{term "Deriv_lang B A"} is regular.
Even more surprising is the fact that for \emph{every} language @{text A}, the language
- consisting of all substrings of @{text A} is regular \cite{Haines69} (see also
+ consisting of all (scattered) substrings of @{text A} is regular \cite{Haines69} (see also
\cite{Shallit08, Gasarch09}).
- A \emph{substring} can be obtained
+ A \emph{(scattered) substring} can be obtained
by striking out zero or more characters from a string. This can be defined
inductively in Isabelle/HOL by the following three rules: