Changes to some math using underscore as subscript, necessary since
the new style file defines underscore as an underscore in tt font.
diff --git a/Doc/Makefile b/Doc/Makefile
index bcc1afe..8559f6f 100644
--- a/Doc/Makefile
+++ b/Doc/Makefile
@@ -13,6 +13,7 @@
 ref:
 	touch ref.ind
 	latex ref
+	./fix_hack ref.idx
 	makeindex ref
 	latex ref
 	dvips ref >ref.ps
@@ -38,7 +39,7 @@
 	sh fix.sh
 
 clean:
-	rm -f @* *~ *.aux *.idx *.ilg *.ind *.log *.toc *.blg *.bbl
+	rm -f @* *~ *.aux *.idx *.ilg *.ind *.log *.toc *.blg *.bbl *.pyc
 	# Sources: .tex, .bib, .sty
 	# Useful results: .dvi, .ps
 
diff --git a/Doc/ref/ref5.tex b/Doc/ref/ref5.tex
index 34dfeb1..7857e95 100644
--- a/Doc/ref/ref5.tex
+++ b/Doc/ref/ref5.tex
@@ -523,12 +523,14 @@
 when $x < y$ is found to be false).
 \indexii{chaining}{comparisons}
 
+\catcode`\_=8
 Formally, $e_0 op_1 e_1 op_2 e_2 ...e_{n-1} op_n e_n$ is equivalent to
 $e_0 op_1 e_1$ \verb\and\ $e_1 op_2 e_2$ \verb\and\ ... \verb\and\
 $e_{n-1} op_n e_n$, except that each expression is evaluated at most once.
 
 Note that $e_0 op_1 e_1 op_2 e_2$ does not imply any kind of comparison
 between $e_0$ and $e_2$, e.g. $x < y > z$ is perfectly legal.
+\catcode`\_=12
 
 The forms \verb\<>\ and \verb\!=\ are equivalent; for consistency with
 C, \verb\!=\ is preferred; where \verb\!=\ is mentioned below
diff --git a/Doc/ref5.tex b/Doc/ref5.tex
index 34dfeb1..7857e95 100644
--- a/Doc/ref5.tex
+++ b/Doc/ref5.tex
@@ -523,12 +523,14 @@
 when $x < y$ is found to be false).
 \indexii{chaining}{comparisons}
 
+\catcode`\_=8
 Formally, $e_0 op_1 e_1 op_2 e_2 ...e_{n-1} op_n e_n$ is equivalent to
 $e_0 op_1 e_1$ \verb\and\ $e_1 op_2 e_2$ \verb\and\ ... \verb\and\
 $e_{n-1} op_n e_n$, except that each expression is evaluated at most once.
 
 Note that $e_0 op_1 e_1 op_2 e_2$ does not imply any kind of comparison
 between $e_0$ and $e_2$, e.g. $x < y > z$ is perfectly legal.
+\catcode`\_=12
 
 The forms \verb\<>\ and \verb\!=\ are equivalent; for consistency with
 C, \verb\!=\ is preferred; where \verb\!=\ is mentioned below