--- a/etnms/etnms.tex Sun Mar 01 20:12:16 2020 +0000
+++ b/etnms/etnms.tex Mon Mar 02 18:08:12 2020 +0000
@@ -1654,13 +1654,47 @@
\end{center}
Here $\gg$ is almost like an $\textit{NFA}$ in the sense that
it simulates the lexing process with respect to different strings.
-\end{itemize}
+
Our hope is that using $\gg$ we can prove the bits
information are not lost when we simplify a regular expression,
so we need to relate $\gg$ with simplifcation, for example,
one of the lemmas we have proved about $\gg$ is that
-
-$\simp$
+\item
+\begin{center}
+$\simp \; a \gg \textit{bs} \iff a \gg \textit{bs}$
+\end{center}
+This could be a step towards our goal, as
+it assures that after simplification none of the
+bitsequence that can be created by
+the original annotated regular expression
+is lost.
+If we could prove the following that would be
+another step towards our proof,
+
+\item
+\begin{center}
+$(\simp \;a) \backslash s \gg \textit{bs} \iff a\backslash s \gg \textit{bs}$
+\end{center}
+
+as it says
+the simplified regular expression after derivatives will
+still have the full capacity of producing bitsequences
+as the unsimplified ones-- pretty much
+the intuition we try to establish.
+And if we could prove
+\item
+\begin{center}
+$a \backslash s \gg \textit{bs} \iff a\backslash_\textit{simp} s \gg \textit{bs}$
+\end{center}
+That would be just a stone's throw away
+from $\blexer \; r \; s = \blexers \; r \; s$.
+
+\end{itemize}
+What we do after we work out
+the proof of the above lemma
+is still not clear. It is one of the next steps we need to
+work on.
+
\subsection{the $\textit{ders}_2$ Function}
If we want to prove the result
\begin{center}
@@ -1670,8 +1704,9 @@
on the structure of the regular expression,
then we need to induct on the case $r_1 \cdot r_2$,
it can be good if we could express $(r_1 \cdot r_2) \backslash s$
-in terms of $r_1 \backslash s$ and $r_2 \backslash s$,
-and this naturally induces the $ders2$ function,
+in terms of $r_1 \backslash s_1$ and $r_2 \backslash s_1$,
+where $s_1$ is a substring of $s$.
+For this we introduce the $\textit{ders2}$ function,
which does a "convolution" on $r_1$ and $r_2$ using the string
$s$.
It is based on the observation that the derivative of $r_1 \cdot r_2$