
EQN(1) EQN(1)
delim $$
NAME
eqn, neqn, checkeq  typeset mathematics
SYNOPSIS
eqn [ dxy ] [ pn ] [ sn ] [ fn ] [ file ] ...
checkeq [ file ] ...
DESCRIPTION
Eqn is a troff(1) preprocessor for typesetting mathematics on a Graphic Systems phototype
setter, neqn on terminals. Usage is almost always
eqn file ...  troff
neqn file ...  nroff
If no files are specified, these programs 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. Delimiters
may be set to characters x and y with the commandline argument dxy or (more commonly)
with `delim xy' between .EQ and .EN. The left and right delimiters may be identical.
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
or circumflexes. 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 $x sub i$, a sub i sup 2 produces $a sub i sup 2$, and e sup {x sup 2 + y sup 2}
gives $e sup {x sup 2 + y sup 2}$.
Fractions are made 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 on arbitrary things: $lim from
{n> inf} sum from 0 to n x sub i$ 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 $left [ x sup 2 + y sup 2 over
alpha right ] ~=~1$. 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 (use
ful for a rightsideonly bracket).
Vertical piles of things are made with pile, lpile, cpile, and rpile: pile {a above b
above c} produces $pile {a above b above c}$. There can be an arbitrary number of ele
ments in a pile. lpile leftjustifies, pile and cpile center, 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 $matrix { lcol { x sub i above y sub 2 } ccol { 1 above 2 } }$. In addition,
there is rcol for a rightjustified column.
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 $x vec ~=~ y dyad$.
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
commandline arguments sn and fn.
Normally subscripts and superscripts are reduced by 3 point sizes from the previous size;
this may be changed by the commandline 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 subse
quent 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 when
ever it appears thereafter. The % may be any character that does not occur in replace
ment.
Keywords like sum ( sum ) int ( int ) inf ( inf ) 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, log are made Roman automatically. Troff(1)
fourcharacter escapes like \(bs () 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.
SEE ALSO
troff(1), tbl(1), ms(7), eqnchar(7)
B. W. Kernighan and L. L. Cherry, Typesetting MathematicsUser's Guide
J. F. Ossanna, NROFF/TROFF User's Manual
BUGS
To embolden digits, parens, etc., it is necessary to quote them, as in `bold "12.3"'.
2/22/74 EQN(1) 
