delim $$
NAME
eqn, neqn, checkeq - format mathematical text
SYNOPSIS
eqn [-dxy] [-pn] [-sn] [-fn] [-Tdest] [files]
neqn [-dxy] [-pn] [-sn] [-fn] [files]
checkeq [files]
DESCRIPTION
eqn is a troff(1) preprocessor for typesetting mathematical
text on a phototypesetter or laser printer, while neqn is
used for the same purpose with nroff on typewriter-like
terminals. Usage is almost always:
eqn files | troff
neqn files | nroff
or equivalent.
If no files are specified (or if - is specified as the last
argument), these programs read the standard input. eqn
prepares output for the typesetter named in the -T flag
option. Currently supported devices are -Taps (Autologic
APS-5), -TX97 (Xerox 9700), -Ti10 (Imagen Imprint-10), and
-Tcat (Wang CAT). Default is -Taps.
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, so they may be
defined in macro packages to get centering, numbering, etc.
It is also possible to designate two characters as
delimiters; subsequent text between delimiters is then
treated as eqn input. Delimiters may be set to characters x
and y with the command-line argument -dxy or (more commonly)
with delim xy between .EQ and .EN. The left and right
delimiters may be the same character; the dollar sign is
often used as such a delimiter. Delimiters are turned off
by delim off. All text that is neither between delimiters
nor between .EQ and .EN is passed through untouched.
The program checkeq reports missing or unbalanced delimiters
and .EQ/.EN pairs.
Tokens within eqn are separated by spaces, tabs, newlines,
braces, double quotes, tildes, and carets. Braces {} are
used for grouping; generally speaking, anywhere a single
character such as x could appear, a complicated construction
enclosed in braces may be used instead. Tilde (~)
represents a full space in the output, caret (^), half as
much.
Subscripts and superscripts are produced with the keywords
sub and sup. Thus,
x sub j
produces:
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eqn(1) eqn(1)
$x sub j$,
a sub k sup 2
produces:
$a sub k sup 2$,
while
$e sup {x sup 2 + y sup 2}$
is made with e sup {x sup 2 + y sup 2}.
Fractions are produced with over:
a over b
yields
$a over b$;
sqrt makes square roots:
1 over sqrt { ax sup 2+bx+c }
results in
$1 over sqrt {ax sup 2 +bx+c}$ .
The keywords from and to introduce lower and upper limits:
lim from {n -> inf} sum from 0 to n x sub i
is made with
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 left and right:
left [ x sup 2 + y sup 2 over alpha right ] ~=~ 1
produces:
$left [ x sup 2 + y sup 2 over alpha right ] ~=~ 1$.
Legal characters after left and right are braces, brackets,
bars, c and f for ceiling and floor, and "" for nothing at
all (useful for a right-side-only bracket). A left thing
need not have a matching right thing.
Vertical piles of things are made with pile, lpile, cpile,
and rpile:
pile { a above b above c }
produces:
$pile {a above b above c}$.
Piles may have arbitrary numbers of elements; lpile left-
justifies, pile and cpile center (but with different
vertical spacing), and rpile right justifies.
Matrixes are made with matrix:
matrix { lcol { x sub i above y sub 2 } ccol { 1 above
2 } }
produces:
$matrix { lcol { x sub i above y sub 2 } ccol { 1 above
2 } }$
In addition, there is rcol for a right-justified column.
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eqn(1) eqn(1)
Diacritical marks are made with dot, dotdot, hat, tilde,
bar, vec, dyad, and under:
x dot = f(t) bar
is
$x dot = f(t) bar$,
y dotdot bar ~=~ n under
is
$y dotdot bar ~=~ n under$,
and
x vec ~=~ y dyad
is
$x vec ~=~ y dyad$.
Point sizes and fonts can be changed with size n or size +n,
roman, italic, bold, and font n. Point sizes and fonts can
be changed globally in a document by gsize n and gfont n, or
by the command-line arguments -sn and -fn.
Normally, subscripts and superscripts are reduced by 3
points from the previous size; this may be changed by the
command-line argument -pn.
Successive display arguments can be lined up. Place mark
before the desired lineup point in the first equation; place
lineup at the place that is to line up vertically in
subsequent equations.
Shorthands may be defined or existing keywords redefined
with define:
define thing % replacement %
defines a new token called thing that will be replaced by
replacement whenever it appears thereafter. The % may be
any character that does not occur in replacement.
Keywords such as sum ( sum ), int ( int ), inf ( inf ), and
shorthands such as >= (>=), != ( != ), and -> (->) are
recognized. Greek letters are spelled out in the desired
case, as in alpha ( alpha ), or GAMMA ( GAMMA ).
Mathematical words such as sin, cos, and log are made Roman
automatically. troff(1) four-character escapes such as \(dd
(‡) may be used anywhere. Strings enclosed in double quotes
("...") are passed through untouched; this permits keywords
to be entered as text, and can be used to communicate with
troff(1) when all else fails. Full details are given in the
manual cited below.
EXAMPLE
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eqn(1) eqn(1)
eqn file1 | troff
would process the file file1 with the preprocessor before
formatting it with troff.
FILES
/bin/eqn
SEE ALSO
mm(1), mmt(1), nroff(1), tbl(1), troff(1), eqnchar(5),
mm(5), mv(5).
``eqn Reference'' and ``Other Text Processing Tools'' in
Oreo Text Processing Tools.
BUGS
To embolden digits, parentheses, etc., it is necessary to
quote them, as in bold "12.3".
See also BUGS under troff(1).
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