eqn(1M) eqn(1M)
NAME
eqn, neqn, checkeq - typeset mathematics
SYNOPSIS
eqn [-dxy] [-pn] [-sn] [-fn] [-Tdev] [-] [file] ...
neqn [-dxy] [-pn] [-sn] [-fn] [-] [file] ...
checkeq [file] ...
DESCRIPTION
The eqn and neqn commands are language processors to assist in
describing equations. eqn is a preprocessor for troff(1M) and is
intended for devices that can print troff's output. neqn is a prepro-
cessor for nroff(1M) and is intended for use with terminals (see the
results in this manual page).
checkeq reports missing or unbalanced delimiters and .EQ/.EN pairs.
If you do not specify files (or if you specify - as the last argu-
ment), 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, so they
may be defined in macro packages to get centering, numbering, etc. It
is also possible to set two characters as "delimiters"; subsequent
text between delimiters is also treated as eqn input.
OPTIONS
-dxy Sets equation delimiters set to characters x and y with the
command line argument. The more common way to do this is with
delimxy between .EQ and .EN. The left and right delimiters may
be identical. Delimiters are turned off by delim off appearing
in the text. All text that is neither between delimiters nor
between .EQ and .EN is passed through untouched.
-fn Change font to n globally in the document. The font can also be
changed globally in the body of the document by using the gfont
directive.
-pn Reduce subscripts and superscripts by n point sizes from the
previous size. In the absence of the -p option, subscripts and
superscripts are reduced by 3 point sizes from the previous size.
-sn Set equations in point size n globally in the document. The
point size can also be changed globally in the body of the
document by using the gsize directive.
-Tdev Prepare output for device dev. If no -T option is present, eqn
looks at the environment variable TYPESETTER to see what the
intended output device is. If no such variable is found in the
environment, a system-dependent default device is assumed. Not
available using neqn.
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eqn(1M) eqn(1M)
USAGE
eqn Language
Tokens within eqn are separated by braces, double quotes, tildes, cir-
cumflexes, SPACE, TAB, or NEWLINE characters. Braces {} are used for
grouping; generally speaking, anywhere a single character like x could
appear, a complicated construction enclosed in braces may be used
instead. Tilde (~) represents a full SPACE in the output, circumflex
(^) half as much.
Subscripts and superscripts are produced with the keywords sub and
sup. Thus 'x sub i' makes xi
2
'a sub i sup 2' produces ai
and 'e sup {x sup 2 + y sup 2}' gives ex2+y2.
a
Fractions are made with over: 'a over b' yields b
sqrt makes square roots: '1 over down 10 sqrt {ax sup 2 +bx+c}'
results in
_____1____
________
\|ax2+bx+c
Although eqn tries to get most things at the right place on the paper,
occasionally you will need to tune the output to make it just right.
In the previous example, a local motion, down 10 was used to get more
space between the square root and the line above it.
The keywords from and to introduce lower and upper limits on arbitrary
things:
n
lim ≳xi
n->oo0
is made with 'lim from {n-> inf } sum from 0 to n x sub i'.
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eqn(1M) eqn(1M)
Left and right brackets, braces, etc. of the right height are made
with left and right:
'P~=~R~left [ 1^-^{1+i sup n } over alpha right ]' produces
|
| 1+in|
P = R |1- α |
|
The right clause is optional. 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).
Vertical piles of things are made with pile, lpile, cpile, and rpile:
'pile {a above b above c}' produces
a
b
c
There can be an arbitrary number of elements in a pile. lpile left-
justifies, pile and cpile center, with different vertical spacing, and
rpile right justifies.
Matrices are made with matrix:
left ( matrix {
ccol { a sub 1 above a sub 2 }
ccol { c sup 2 above d sup 2 }
} right )
produces
( )
|a1 c2|
| |
|a2 d2|
( )
In addition, there is rcol for a right-justified column.
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eqn(1M) eqn(1M)
Diacritical marks are made with dot, dotdot, hat, tilde, bar, vec,
dyad, and under:
. ____
'x dot = f(t) bar' yields x=f(t),
..
'y dotdot bar ~=~ n under' yields y = n, and
_ _
'x vec ~=~ y dyad' yields x = y
Sizes and font can be changed with size n or size ±n, roman, italic,
bold, and font n. Size and fonts can be changed globally in a document
by gsize n and gfont n, or by the command-line arguments -sn and -fn.
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 which will be replaced by replacement
whenever it appears thereafter. The % may be any character that does
not occur in replacement.
Keywords like sum (≳), int (∫), inf (oo), and shorthands like >= (>),
-> (->), and != (≠) are recognized. Greek letters are spelled out in
the desired case, as in alpha or GAMMA. Mathematical words like sin,
cos, and log are made Roman automatically. troff(1M) four-character
escapes like \(dd (‡) can 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 when all
else fails.
EXAMPLES
eqn [options] files | troff [options] | [phototypesetter]
neqn [options] file ... | nroff [options] | [printer]
NOTES
To embolden digits, parentheses, etc. it is necessary to quote them,
as in bold "12.3". When you use eqn with the mm macro package,
displayed equations must appear only inside displays.
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eqn(1M) eqn(1M)
SEE ALSO
neqn(1M), nroff(1M), troff(1M), eqnchar(5).
REFERENCES
B. W. Kernighan, L. L. Cherry, Typesetting Mathematics - User's Guide
(2nd Ed.)
D. Dougherty, T. O'Reilly, UNIX TEXT PROCESSING, Hayden Books, Indi-
anapolis, Indiana 46268 USA, ISBN 0-672-46291-5
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