neqn, checkeq - Typesets mathematical equations and
expressions
neqn [-dxy] [-pn] [-sn] [-fn] [file...] | nroff...
checkeq [file...]
The neqn command is an nroff(1) preprocessor for displaying
mathematical symbols and equations on terminals.
Usage almost always involves preprocessing an nroff source
file with neqn and then piping the output through nroff.
Note
The neqn command formatting works best on typesetting
devices. Your terminal might not be equipped to display
equations and other math symbols in a meaningful way. In
fact, you might have difficulty viewing the symbols and
examples included in this reference page.
If no files are specified, neqn reads from the standard
input. A line beginning with marks the start of an equation;
at the beginning of a line marks the end of an equation.
Neither of these lines is altered, so they can be
defined in macro packages to produce centering, numbering,
and so on.
It is also possible to set two characters as delimiters;
subsequent text between delimiters is also treated as
input to neqn. Delimiters may be set to any two characters,
such as x and y, with the command-line argument -dxy
or more commonly by placing delim xy between and be identical.
Delimiters are turned off by delim off. All text
that is neither between delimiters nor between and is
passed through untouched.
The program checkeq reports missing or unbalanced delimiters
and pairs.
Tokens within neqn are separated by spaces, tabs, newlines,
braces, double quotation marks, tildes, or circumflexes.
Braces { } are used for grouping. Generally
speaking, anywhere a single character could appear, a complicated
construction enclosed in braces can be used
instead. The tilde (~) represents a full space in the
output; the circumflex (^) half as much.
Subscripts and superscripts are produced with the keywords
sub and sup.
Fractions use the keyword over.
The sqrt keyword creates square roots.
The keywords from and to are used to express lower and
upper limits.
Left and right brackets, braces, and so forth that
encompass more than one line are created with the left and
right keywords and tildes. Legal characters to use with
left and right are {, }, [, ], |, c (ceiling), f (floor),
and , meaning `nothing' (to use with the left keyword when
you want brackets or braces on the right side only). The
right keyword clause is optional.
Vertical piles of things are made with pile, lpile, rpile,
and cpile. There can be an arbitrary number of elements
in a pile. You use lpile to left-justify a vertical
grouping and rpile to right-justify one. The pile and
cpile keywords create centered piles but have different
vertical spacing.
You use the matrix keyword to create matrixes. The lcol,
ccol, and col keywords are used with matrix to specify the
alignment within the matrix; that is a left-justified column,
centered column, and right-justified column, respectively.
Diacritical marks are made with the following keywords:
dot Produces a period (.) over the character preceding the
keyword.
dotdot Produces two periods (..) over the character preceding the
keyword.
hat Produces a circumflex (^) over the character preceding the
keyword.
tilde Produces a tilde (~) over the character preceding the keyword.
bar Produces a horizontal bar over the character preceding the
keyword.
vec Produces a left-pointing arrow over the character preceding
the keyword.
dyad Produces a bidirectional arrow over the character preceding
the keyword.
under Produces an underscore under the character preceding the
keyword.
Size and font changes are made with the following keywords:
size n Specifies the size as n points.
size+n Increases the size n points.
size-n Decreases the size n points.
roman Uses roman type font.
italic Uses italic type font.
bold Uses bold type font.
font n Uses the specified type font.
Size and font can be changed globally in a document by
using the gsize n and the gfont n keyword expressions or
by the command-line arguments -s n and -f n.
Normally subscripts and superscripts are reduced by three
point sizes from the previous size. You can change this
default with the -p n command-line argument.
To aline successive display arguments, place the mark keyword
before the desired lineup point in the first equation.
Then place the lineup keyword at the place that is
to line up vertically in subsequent equation lines.
New keywords or new forms of existing keywords can be
defined with the define keyword. For example, the following
define expression defines the new keyword cc to be C
Language:
define cc % C Language %
Whenever cc appears in the source file, processing with
neqn causes C Language to appear in the preprocessed or
output file. Note that the delimiting character surrounding
the replacement string can be any character as long as
it does not appear in the replacement string itself.
The following keywords are also recognized for typeset
output:
sum Produces a large Greek sigma indicating summation.
int Produces an integration sign.
inf Produces an infinity sign.
>= Produces a greater-than-or-equals sign.
<= Produces a less-than-or-equals sign.
-> Produces a right pointing arrow.
<- Produces a left pointing arrow.
!= Produces a not equal sign.
Greek letters are spelled out in the desired case, for
example, alpha or GAMMA. Mathematical words like sin, cos,
log are output in roman type automatically. Strings
enclosed in double quotation marks ("...") are passed
through untouched; this feature permits keywords to be
entered as text.
To embolden digits, parentheses, and so on, you must
enclose them in quotation marks after the keyword bold.
For example:
bold "12.3".
Input and output for x with subscript i:
x sub i -> x
i Input and output for x with subscript
i and superscript 2:
x sub i sup 2 -> x2
i Input and output for e
with a superscript of x squared plus y squared:
2 2
x +y e sup {x sup
2 + y sup 2} -> e Input and output for the
fraction q over r:
q q over r -> _
r Input and output for the fraction
of 1 over the square root of a polynomial that
includes a superscript:
1 1 over sqrt
{as sup 2 +bx+c} -> _________
2
\|ax +bx+c Input
and output for an expression with a lower and upper
limit:
n
lim from {n-> inf } sum from 0 to n x sub i ->
lim Rxi
n->oo0
Input and output for an expression with large left
and right braces:
{
2 y }
_2
left {x sup 2 = y sup 2 over alpha right} ~=~ 1 ->
{x +A } = 1
{
} Input and output for a "pile" expression:
a pile { a
above b above c } -> b
c Input and
output for an expression with a matrix:
matrix {lcol { x sub i above y sub 2 } ccol { 1
above 2 }} ->
x 1
i
y 2
2
nroff(1), tbl(1), ms(5)
neqn(1)
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