PWB1/usr/man/man1/realeqn

.EQ
delim $$
.EN
.th EQN I 5/31/77
.sh NAME
eqn  \*-  typeset mathematics
.sh SYNOPSIS
.bd eqn
[ file ] ...
.sh DESCRIPTION
.it Eqn
is a
.it troff\^\c
(I)
preprocessor
for typesetting mathematics
on the Graphics Systems, Inc. phototypesetter.
Usage is almost always
.s3
	eqn file ... | troff
.s3
If no files are specified, 
.it eqn
reads from the standard input.
A line beginning with ``.EQ'' marks the start of an equation;
the end of an equation
is marked by a line beginning with ``.EN''.
Neither of these lines is altered or defined by
.it eqn,
so you can define them yourself
in
.it troff\^\c
(I)
to get
centering, numbering, etc.
All other lines are treated as comments, and passed through
untouched.
.s3
Spaces, tabs, new-lines, braces, double quotes,
tilde, and circumflex are the only delimiters.
Braces ``{}'' are used for grouping.
Use tildes ``~'' to get extra spaces in an equation.
.s3
.vs 13p
Subscripts and superscripts are produced with the keywords
.bd sub
and
.bd sup.
Thus
.it "x sub i" 
makes
$x sub i$, 
.it "a sub i sup 2"
produces
$a sub i sup 2$,
and
.it "e sup {x sup 2 + y sup 2}"
gives
$e sup {x sup 2 + y sup 2}$.
Fractions are made with
.bd over.
.it "a over b"
is $a over b$ and
.it "1 over sqrt {ax sup 2 +bx+c}"
is
$1 over sqrt {ax sup 2 +bx+c}$ ;
.bd sqrt
makes square roots.
.s3
The keywords
.bd from
and
.bd to
introduce lower and upper
limits on arbitrary things:
$lim from {n-> inf} sum from 0 to n x sub i$
is made with
.it "lim from {n-> inf} sum from 0 to n x sub i."
Left and right brackets, braces, etc., of the right height are made with
.bd left
and
.bd right:
.it "left [ x sup 2 + y sup 2 over alpha right ] ~=~1"
produces
.if n .s3
$left [ x sup 2 + y sup 2 over alpha right ] ~=~1$.
The
.bd right
clause is optional.
.s3
Vertical piles of things are made with 
.bd "pile, lpile, cpile,"
and
.bd rpile:
.it "pile {a above b above c}"
produces
$pile {a above b above c}$.
There can be an arbitrary number of elements in a pile.
.bd lpile
left-justifies,
.bd pile
and
.bd cpile
center, with different vertical spacing,
and 
.bd rpile
right justifies.
.s3
.vs 12p
Diacritical marks are made with
.bd dot,
.bd dotdot,
.bd hat,
.bd bar:
.it "x hat = f(t) bar"
is
$x hat = f(t) bar$.
Default sizes and fonts can be changed with
.bd "size n"
and various of
.bd roman,
.bd italic,
and
.bd bold.
.s3
Keywords like 
.it sum
.EQ
( sum ),
.EN
.it int
.EQ
( int ),
.EN
.it inf
.EQ
( inf ),
.EN
and shorthands like
>=,
.EQ
(>=),
.EN
\*->,
.EQ
(->),
.EN
!=,
.EQ
( != )
.EN
are recognized.
Spell out Greek letters in the desired case, as in
.it "alpha, GAMMA."
Mathematical words like 
.it sin,
.it cos,
.it log
are made Roman automatically.
.it Troff\^\c
(I)
four-character escapes like \\(ua (\(ua \*- for ``up arrow'')
can be used anywhere.
Strings enclosed in double quotes "..."
are passed through untouched.
.sh "SEE ALSO"
.it "Typesetting Mathematics \\- User's Guide (2nd Edition)"
by B. W. Kernighan and L. L. Cherry
.br
.it "New Graphic Symbols for EQN and NEQN"
by C. Scrocca
.br
.it "N\s-2ROFF/TROFF\s0 User's Manual"
by J. F. Ossanna
.br
troff(I), neqn(I)
.sh BUGS
Undoubtedly.
Watch out for small or large point sizes \*-
it's tuned too well for size 10.
Be cautious if inserting horizontal or vertical motions,
and of backslashes in general.