NAME

neqn − format mathematical text for nroff

SYNOPSIS

neqn [ −dxy ] [ −sn ] [ −fn ] [ −pn ] [ file ...  ]

DESCRIPTION

Neqn is a preprocessor for nroff(1) for typesetting mathematical text on typewriter-like terminals. Usage is almost always:

neqn files │ nroff

or equivalent. 

If no files are specified (or if − is specified as the last argument), nroff 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 designate two characters as delimiters; subsequent text between delimiters is then treated as neqn 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. 

Tokens within neqn are separated by spaces, tabs, new-lines, braces, double quotes, tildes, and circumflexes.  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, circumflex (^) half as much. 

Subscripts and superscripts are produced with the keywords sub and sup.  Thus:

x sub j produces xj

and

a sub k sup 2 produces ak2,

while:

ex2+y2 is made by typing e sup {x sup 2 + y sup 2}.

Fractions are produced by using over:

a over b yieldsa over b;

sqrt produces square roots:

1 over sqrt {ax sup 2+bx+c} results in 1 over √ax2+bx+c . 

The keywords from and to introduce lower and upper limits:

limn→∞ n∑0 xi is made with lim from {n −> inf } sum from 0 to n x  sub i.

Left and right brackets, braces, etc., of proper height are made with left and right:

left [ x sup 2 + y sup 2 over alpha right ] ~=~ 1 ­produces
⎡
⎢
⎣x sup 2 + y sup 2 over α
⎤
⎥
⎦ = 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 a
b
c. 

Piles may have arbitrary numbers of elements; lpile left justifies, pile and cpile center (but with different vertical spacing), and rpile right justifies. 

Matrices are made with matrix:

matrix { lcol { x sub i above y sub 2 } ccol { 1 above 2 } } ­produces xi
y21
2. 

In addition, there is rcol for a right-justified column. 

Diacritical marks are made with dot, dotdot, hat, tilde, bar, vec, dyad, and under:

x dot = f(t) bar is ẋ=f(t),
y dotdot bar ~=~ n under is ÿ = n, and
x vec ~=~ y dyad is x⃗ = y⃡. 

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 (∑),int (∫),inf (∞),and shorthands such as >= (≥),!= (≠),and −> (→)are recognized.  Greek letters are spelled out in the desired case, as in alpha (α),or GAMMA (Γ).Mathematical words such as sin, cos, and log are made Roman automatically.  Nroff(1) four-character escapes such as \(dd (‡) and \(bu (•) 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 nroff(1) when all else fails. Details are given in the manuals cited below.

WARNINGS

To embolden digits, parentheses, etc., it is necessary to quote them, as in bold "12.3". 
See also WARNINGS under nroff(1).

SEE ALSO

Typesetting Mathematics−User’s Guide, by B. W. Kernighan and L. L. Cherry. 
New Graphic Symbols for EQN and NEQN, by C. Scrocca.  mm(1), nroff(1), tbl(1), mm(5).

INTERNATIONAL SUPPORT

8- and 16-bit data, 8-bit file names, messages. 

Hewlett-Packard Company  —  May 11, 2021