EQN(1)							      General Commands Manual							    EQN(1)

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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 phototypesetter, 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 command-line 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 (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 $pile {a above b above c}$.   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: 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.

       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  docu-
       ment by gsize n and gfont n, or by the command-line arguments -sn and -fn.

       Normally  subscripts and superscripts are reduced by 3 point sizes 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 which
       will be replaced by replacement whenever it appears thereafter.	The % may be any character that does not occur in replacement.

       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) four-
       character 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 Mathematics--User'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)