diff -urN eqn-v7-pure/Makefile eqn-v7-hacked/Makefile
--- eqn-v7-pure/Makefile	1969-12-31 18:00:00.000000000 -0600
+++ eqn-v7-hacked/Makefile	2022-07-06 05:34:09.196687749 -0500
@@ -0,0 +1,21 @@
+# Set this macro to where your groff executable is located.  For best
+# results, ensure that it locates an s.tmac file with some fixes applied
+# (Savannah #62686, #62687, #62688).
+GROFF:=/home/branden/src/GIT/groff/build/test-groff
+GROFFOPTS:=-ww -e -ms -M . -m sbtl -P -e -P -pletter -T pdf
+
+ALL=eqnsystem.pdf eqnuser.pdf
+
+all: $(ALL)
+
+EQNSYSTEMSRCS:=e.mac e0 e1 e2 e3 e4 e5 e6 e7
+EQNUSERSRCS:=g.mac g0 g1 g2 g3 g4 g5
+
+eqnsystem.pdf: sbtl.tmac $(EQNSYSTEMSRCS)
+	$(GROFF) $(GROFFOPTS) $(EQNSYSTEMSRCS) >$@
+
+eqnuser.pdf: sbtl.tmac $(EQNUSERSRCS)
+	$(GROFF) $(GROFFOPTS) $(EQNUSERSRCS) >$@
+
+clean:
+	rm -f $(ALL)
diff -urN eqn-v7-pure/e0 eqn-v7-hacked/e0
--- eqn-v7-pure/e0	2022-07-01 23:44:19.064152612 -0500
+++ eqn-v7-hacked/e0	2022-07-06 05:14:01.254315338 -0500
@@ -1,11 +1,11 @@
 .nr PS 9
 .nr VS 11
-....ND "Revised  April, 1977"
+.\"...ND "Revised  April, 1977"
 .EQ
 delim $$
 gsize 9
 .EN
-....TR 17
+.\"...TR 17
 .TL
 A System for Typesetting Mathematics
 .AU
diff -urN eqn-v7-pure/e1 eqn-v7-hacked/e1
--- eqn-v7-pure/e1	2022-07-01 23:44:19.064152612 -0500
+++ eqn-v7-hacked/e1	2022-07-06 05:09:20.715604554 -0500
@@ -20,8 +20,9 @@
 is the multiplicity of characters,
 sizes, and fonts.
 An expression such as
+.\" Added space before "->", GBR 2022
 .EQ
-lim from {x-> pi /2} ( tan~x) sup{sin~2x}~=~1
+lim from {x -> pi /2} ( tan~x) sup{sin~2x}~=~1
 .EN
 requires an intimate mixture of roman, italic and greek letters, in three sizes,
 and a special character or two.
diff -urN eqn-v7-pure/g.mac eqn-v7-hacked/g.mac
--- eqn-v7-pure/g.mac	2022-06-30 16:28:19.984161912 -0500
+++ eqn-v7-hacked/g.mac	2022-07-01 11:44:16.157564585 -0500
@@ -2,6 +2,7 @@
 .de SC
 .NH
 \\$1 \\$2 \\$3 \\$4 \\$5 \\$6 \\$7 \\$8 \\$9 
+.pdfbookmark 1 \\$*
 ..
 .de UC
 \&\\$3\s-2\\$1\\s+2\\$2
diff -urN eqn-v7-pure/g0 eqn-v7-hacked/g0
--- eqn-v7-pure/g0	2022-06-30 18:38:30.234150358 -0500
+++ eqn-v7-hacked/g0	2022-07-08 19:19:39.087648085 -0500
@@ -1,9 +1,26 @@
+.\" Adapted for groff by G. Branden Robinson, 2022-06-30/07-02.  Thanks
+.\" to Deri James for PDF support.
+.\" These values, used with URW Times fonts at 10 points, produce column
+.\" and page breaks nearly identical to the C/A/T typeset original.
+.nr LL 5.4i
+.nr PO 1.55i
+.\" Define a fake Bell System logo.
+.char \[bs] \o'\[ci]|'
 .EQ
 delim $$
 .EN
-\".ND "June 2, 1976"
-.RP
-\".TM "76-1273-4 76-1271-4" 39199 39199-11
+.
+.af year 0000
+.af mo 00
+.af dy 00
+.ND "August 15, 1978 \fI(retypeset with \fPgroff\fI\
+ \n[year]-\n(mo-\n(dy)"
+.RP no \" suppress repeat of document description on first body page
+.\" Force page 1 to be numbered; it follows the cover page and the Unix
+.\" Programmer's Manual page headings (which these sources don't produce
+.\" anyway) are not appropriate for this document in isolation.
+.nr pg*P1 1
+.\"TM "76-1273-4 76-1271-4" 39199 39199-11
 .TL
 Typesetting Mathematics _ User's Guide
 \&\ \ \ \ \ (Second\ Edition)
@@ -12,13 +29,18 @@
 .AI
 .MH
 .AB
-.in
-.ll
+.\" This document uses the full page width for the abstract.
+.\"in
+.\"ll
+.nr 0:li 0
+.nr 0:ri 0
+.pdfinfo /Title Typesetting Mathematics - User's Guide (Second Edition)
+.pdfinfo /Author Brian W. Kernighan and Lorinda L. Cherry
 .PP
 This is the user's guide for a system for typesetting
 mathematics,
 using
-the phototypesetters on the
+the \%photo\%typesetters on the
 .UX
 and
 .UC GCOS
@@ -28,35 +50,42 @@
 designed to be easy to use
 by people who know neither mathematics nor typesetting.
 Enough of the language to set in-line expressions like
-$lim from {x-> pi /2} ( tan~x) sup{sin~2x}~=~1$
+.\" Correct missing space after n for GNU eqn.  GBR, 2022.
+$lim from {x -> pi /2} ( tan~x) sup{sin~2x}~=~1$
 or display equations like
-.in .5i
+.\"in .5i
 .EQ I
 G(z)~mark =~ e sup { ln ~ G(z) }
 ~=~ exp left ( 
 sum from k>=1 {S sub k z sup k} over k right )
 ~=~  prod from k>=1 e sup {S sub k z sup k /k}
 .EN
+.\" Use "cdots" for ellipses on the math axis; "ldots" on the baseline.
+.\" Redefine them to space them more widely.  Use ~ more generously than
+.\" K&C; groff eqn tends to horizontally pack more tightly.  Keep the
+.\" copy of this in file "g4" in sync.
 .EQ I
+define cdots "{ \[md]~\[md]~\[md] }"
+define ldots "{ .~.~. }"
 lineup = left ( 1 + S sub 1 z + 
-{ S sub 1 sup 2 z sup 2 } over 2! + ... right )
-left ( 1+ { S sub 2 z sup 2 } over 2
+{ S sub 1 sup 2 z sup 2 } over 2! + ~ cdots right )
+~ left ( 1+ { S sub 2 z sup 2 } over 2
 + { S sub 2 sup 2 z sup 4 } over { 2 sup 2 cdot 2! }
-+ ... right ) ...
++ ~ cdots right ) ~ cdots
 .EN
 .EQ I
 lineup =  sum from m>=0 left (
 sum from
-pile { k sub 1 ,k sub 2 ,..., k sub m  >=0
+pile { k sub 1 ,k sub 2 , ~ ldots ~ , k sub m  >=0
 above
-k sub 1 +2k sub 2 + ... +mk sub m =m}
+k sub 1 +2k sub 2 + ~ cdots ~ +mk sub m =m}
 { S sub 1 sup {k sub 1} } over {1 sup k sub 1 k sub 1 ! } ~
 { S sub 2 sup {k sub 2} } over {2 sup k sub 2 k sub 2 ! } ~
-...
+cdots
 { S sub m sup {k sub m} } over {m sup k sub m k sub m ! } 
-right ) z sup m
+right ) ~ z sup m
 .EN
-.in 0
+.\"in 0
 can be learned in an hour or so.
 .PP
 The language interfaces directly with
@@ -73,11 +102,13 @@
 .UC UNIX
 formatter
 .UC NROFF
-to set mathematical expressions on 
+to set mathematical \%expressions on 
 .UC DASI
 and
 .UC GSI
 terminals
 and Model 37 teletypes.
+.\" TODO: Force the first body page to be numbered "2" to align with PDF
+.\" page numbers.
 .AE
-.CS 11 0 11 0 0 3
+.\"CS 11 0 11 0 0 3
diff -urN eqn-v7-pure/g1 eqn-v7-hacked/g1
--- eqn-v7-pure/g1	2022-06-30 16:28:19.984161912 -0500
+++ eqn-v7-hacked/g1	2022-07-01 20:39:52.463882265 -0500
@@ -1,3 +1,6 @@
+.\" Force extra-large blank area at top of page to match original.
+.sp 10v
+.nr MINGW 5.875n
 .if t .2C
 .SC Introduction
 .PP
@@ -400,6 +403,7 @@
 e sup {i omega t}
 .P2
 is
+.\" This equation got lost in the V7 Volume 2 manual!
 .EQ
 e sup {i omega t}
 .EN
@@ -523,6 +527,7 @@
 .EQ
 sqrt a+b + 1 over sqrt {ax sup 2 +bx+c}
 .EN
+.KS
 Warning _ square roots of tall quantities look lousy,
 because a root-sign 
 big enough to cover the quantity is
@@ -534,6 +539,7 @@
 .EQ
 sqrt{a sup 2 over b sub 2}
 .EN
+.KE
 Big square roots are generally better written as something
 to the power \(12:
 .EQ
@@ -603,6 +609,7 @@
 lim from {n \(mi> inf} x sub n =0
 .P2
 is
+.\" Correct missing space after n for GNU eqn.  GBR, 2022.
 .EQ
-lim from {n-> inf} x sub n =0
+lim from {n -> inf} x sub n =0
 .EN
diff -urN eqn-v7-pure/g2 eqn-v7-hacked/g2
--- eqn-v7-pure/g2	2022-06-30 16:28:19.984161912 -0500
+++ eqn-v7-hacked/g2	2022-06-30 22:42:34.436500637 -0500
@@ -181,9 +181,11 @@
 is not subject to any of the font changes and spacing
 adjustments normally done by the equation setter.
 This provides a way to do your own spacing and adjusting if needed:
+.KS
 .P1
 italic "sin(x)" + sin (x)
 .P2
+.KE
 is
 .EQ
 italic "sin(x)" + sin (x)
@@ -281,6 +283,7 @@
 if at all possible.
 Thus, for example,
 you can say
+.KS
 .P1
 ^EQ I
 x+y mark = z
@@ -296,6 +299,7 @@
 .EQ I
 x lineup = 1
 .EN
+.KE
 For reasons too complicated to talk about,
 when you use
 .UC EQN
@@ -428,11 +432,18 @@
 right ]
 .P2
 will make
+.\" Cheat #1: AT&T eqn stacked piles more tightly than GNU eqn.
 .EQ
+set baseline_sep 1v
 A ~=~ left [
 pile { a above b above c } ~~ pile { x above y above z }
 right ]
 .EN
+.\" Reset equation baseline separation to the default, which is not
+.\" documented anywhere and has no syntactical access.  :-/
+.EQ
+set baseline_sep 140
+.EN
 The elements of the pile (there can be as many as you want)
 are centered one above another, at the right height for
 most purposes.
@@ -466,6 +477,9 @@
 .ul
 cpiles
 than it is for ordinary piles.
+.\" Cheat #2: Shrink the display distance a bit to fit this display on
+.\" the page.
+.nr DD -0.25v
 .P1 2
 roman sign (x)~=~ 
 left {
@@ -473,6 +487,7 @@
    ~~ lpile
     {if~x>0 above if~x=0 above if~x<0}
 .P2
+.nr DD +0.25v
 makes
 .EQ
 roman sign (x)~=~ 
diff -urN eqn-v7-pure/g4 eqn-v7-hacked/g4
--- eqn-v7-pure/g4	2022-06-30 16:28:19.984161912 -0500
+++ eqn-v7-hacked/g4	2022-07-01 20:51:50.768616704 -0500
@@ -2,10 +2,10 @@
 .PP
 Here is the complete source for the three display equations
 in the abstract of this guide.
-.sp
-.nf
+.DS L
 .ps -2
 .vs -2
+.\" Keep the copy of this in file "g0" in sync.
  .EQ I
  G(z)~mark =~ e sup { ln ~ G(z) }
  ~=~ exp left ( 
@@ -13,26 +13,27 @@
  ~=~  prod from k>=1 e sup {S sub k z sup k /k}
  .EN
  .EQ I
+ define cdots "{ \[md]~\[md]~\[md] }"
+ define ldots "{ .~.~. }"
  lineup = left ( 1 + S sub 1 z + 
- { S sub 1 sup 2 z sup 2 } over 2! + ... right )
- left ( 1+ { S sub 2 z sup 2 } over 2
+ { S sub 1 sup 2 z sup 2 } over 2! + ~ cdots right )
+ ~ left ( 1+ { S sub 2 z sup 2 } over 2
  + { S sub 2 sup 2 z sup 4 } over { 2 sup 2 cdot 2! }
- + ... right ) ...
+ + ~ cdots right ) ~ cdots
  .EN
  .EQ I
  lineup =  sum from m>=0 left (
  sum from
- pile { k sub 1 ,k sub 2 ,..., k sub m  >=0
+ pile { k sub 1 ,k sub 2 , ~ ldots ~ , k sub m  >=0
  above
- k sub 1 +2k sub 2 + ... +mk sub m =m}
+ k sub 1 +2k sub 2 + ~ cdots ~ +mk sub m =m}
  { S sub 1 sup {k sub 1} } over {1 sup k sub 1 k sub 1 ! } ~
  { S sub 2 sup {k sub 2} } over {2 sup k sub 2 k sub 2 ! } ~
- ...
+ cdots
  { S sub m sup {k sub m} } over {m sup k sub m k sub m ! } 
- right ) z sup m
+ right ) ~ z sup m
  .EN
-.sp
-.fi
+.DE
 .ps +2
 .vs +2
 .SC "Keywords, Precedences, Etc."
@@ -61,7 +62,7 @@
 Digits, parentheses, brackets, punctuation marks, and these mathematical words
 are converted
 to Roman font when encountered:
-.P1
+.P1 3 \" reduce indentation, GBR 2022
 sin  cos  tan  sinh  cosh  tanh  arc
 max  min  lim  log  ln  exp
 Re  Im  and  if  for  det
@@ -140,7 +141,7 @@
 .sp
 .nf
 .in .2i
-.ta .7i 1.4i 2.1i
+.ta .7i 1.4i 2.0i \" reduce last tab stop, GBR 2022
 above	17, 18	lpile	17
 back	21	mark	15
 bar	13	matrix	18
diff -urN eqn-v7-pure/sbtl.tmac eqn-v7-hacked/sbtl.tmac
--- eqn-v7-pure/sbtl.tmac	1969-12-31 18:00:00.000000000 -0600
+++ eqn-v7-hacked/sbtl.tmac	2022-06-30 21:04:56.846814044 -0500
@@ -0,0 +1,15 @@
+.de MH
+Bell Laboratories
+Murray Hill, New Jersey 07974
+..
+.de UX
+.nr btl*seen-UX-macro 0
+.ds btl*UX-suffix \(dg\"
+\s[\\n[.s]*8u/10u]UNIX\s0\\$1\\*[btl*UX-suffix]
+.if !\\n[btl*seen-UX-macro] \{\
+.  FS \\*[btl*UX-suffix]
+.  nop UNIX is a Trademark of Bell Laboratories.\" sic
+.  FE
+.  nr btl*seen-UX-macro 1
+.\}
+..