.TH EQN 1 | |

.EQ | |

delim $$ | |

.EN | |

.SH NAME | |

eqn \- typeset mathematics | |

.SH SYNOPSIS | |

.B eqn | |

[ | |

.I option ... | |

] | |

[ | |

.I file ... | |

] | |

.SH DESCRIPTION | |

.I Eqn | |

is a | |

.IR troff (1) | |

preprocessor | |

for typesetting mathematics | |

on a typesetter. | |

Usage is almost always | |

.IP | |

.L | |

eqn file ... | troff | |

.PP | |

If no files are specified, | |

.I eqn | |

reads from the standard input. | |

.I Eqn | |

prepares output for the typesetter | |

named in the | |

.BI -T dest | |

option (default | |

.BR -Tutf ; | |

see | |

.IR troff (1)). | |

When run with other preprocessor filters, | |

.I eqn | |

usually comes last. | |

.PP | |

A line beginning with | |

.B .EQ | |

marks the start of an equation; | |

the end of an equation | |

is marked by a line beginning with | |

.BR .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'; | |

text between delimiters is also | |

.I eqn | |

input. | |

Delimiters may be set to characters | |

.I x | |

and | |

.I y | |

with the option | |

.BI -d xy | |

or (more commonly) with | |

.B delim | |

.I xy | |

between | |

.B .EQ | |

and | |

.BR .EN . | |

Left and right delimiters may be identical. | |

(They are customarily taken to be | |

$font L "$$" )$. | |

Delimiters are turned off by | |

.LR "delim off" . | |

All text that is neither between delimiters nor between | |

.B .EQ | |

and | |

.B .EN | |

is passed through untouched. | |

.PP | |

Tokens within | |

.I 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 | |

.L x | |

could appear, a complicated construction | |

enclosed in braces may be used instead. | |

Tilde | |

.L ~ | |

represents a full space in the output, | |

circumflex | |

.L ^ | |

half as much. | |

.PP | |

.vs 13p | |

Subscripts and superscripts are produced with the keywords | |

.B sub | |

and | |

.BR sup . | |

Thus | |

.L "x sub i" | |

makes | |

$x sub i$, | |

.L "a sub i sup 2" | |

produces | |

$a sub i sup 2$, | |

and | |

.L "e sup {x sup 2 + y sup 2}" | |

gives | |

$e sup {x sup 2 + y sup 2}$. | |

.PP | |

.B Over | |

makes fractions: | |

.L "a over b" | |

yields $a over b$. | |

.PP | |

.B Sqrt | |

produces square roots: | |

.L "1 over sqrt {ax sup 2 +bx+c}" | |

results in | |

$1 over sqrt {ax sup 2 +bx+c}$ . | |

.PP | |

The keywords | |

.B from | |

and | |

.B to | |

introduce lower and upper | |

limits on arbitrary things: | |

$lim from {n -> inf} sum from 0 to n x sub i$ | |

is made with | |

.LR "lim from {n -> inf} sum from 0 to n x sub i" . | |

.PP | |

Left and right brackets, braces, etc., of the right height are made with | |

.B left | |

and | |

.BR right : | |

.L "left [ x sup 2 + y sup 2 over alpha right ] ~=~1" | |

produces | |

$left [ x sup 2 + y sup 2 over alpha right ] ~=~1$. | |

The | |

.B right | |

clause is optional. | |

Legal characters after | |

.B left | |

and | |

.B right | |

are braces, brackets, bars, | |

.B c | |

and | |

.B f | |

for ceiling and floor, | |

and | |

.B | |

"" | |

for nothing at all (useful for a right-side-only bracket). | |

.PP | |

Vertical piles of things are made with | |

.BR pile , | |

.BR lpile , | |

.BR cpile , | |

and | |

.BR rpile : | |

.L "pile {a above b above c}" | |

produces | |

$pile {a above b above c}$. | |

There can be an arbitrary number of elements in a pile. | |

.B lpile | |

left-justifies, | |

.B pile | |

and | |

.B cpile | |

center, with different vertical spacing, | |

and | |

.B rpile | |

right justifies. | |

.PP | |

Matrices are made with | |

.BR matrix : | |

.L "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 | |

.B rcol | |

for a right-justified column. | |

.PP | |

.vs 12p | |

Diacritical marks are made with | |

.BR prime , | |

.BR dot , | |

.BR dotdot , | |

.BR hat , | |

.BR tilde , | |

.BR bar , | |

.BR under , | |

.BR vec , | |

.BR dyad , | |

and | |

.BR under : | |

.L "x sub 0 sup prime = f(t) bar + g(t) under" | |

is | |

$x sub 0 sup prime = f(t) bar + g(t) under$, | |

and | |

.L "x vec = y dyad" | |

is | |

$x vec = y dyad$. | |

.PP | |

Sizes and fonts can be changed with prefix operators | |

.B size | |

.IR n , | |

.B size | |

.BI ± n \f1, | |

.BR fat , | |

.BR roman , | |

.BR italic , | |

.BR bold , | |

or | |

.BR font | |

.IR n . | |

Size and fonts can be changed globally in a document by | |

.B gsize | |

.I n | |

and | |

.B gfont | |

.IR n , | |

or by the command-line arguments | |

.BI -s n | |

and | |

.BI -f n\f1. | |

.PP | |

Normally subscripts and superscripts are reduced by | |

3 point sizes from the previous size; | |

this may be changed by the command-line argument | |

.BI -p n\f1. | |

.PP | |

Successive display arguments can be lined up. | |

Place | |

.B mark | |

before the desired lineup point in the first equation; | |

place | |

.B lineup | |

at the place that is to line up vertically in subsequent equations. | |

.PP | |

Shorthands may be defined | |

or existing keywords redefined with | |

.BR define : | |

.L define | |

.I thing | |

.L % | |

.I replacement | |

.L % | |

defines a new token called | |

.I thing | |

which will be replaced by | |

.I replacement | |

whenever it appears thereafter. | |

The | |

.L % | |

may be any character that does not occur in | |

.LR replacement . | |

.PP | |

Keywords like | |

.L sum | |

.EQ | |

( sum ), | |

.EN | |

.L int | |

.EQ | |

( int ), | |

.EN | |

.L inf | |

.EQ | |

( inf ), | |

.EN | |

and shorthands like | |

.L >= | |

.EQ | |

(>=), | |

.EN | |

.L -> | |

.EQ | |

(->), | |

.EN | |

and | |

.L != | |

.EQ | |

( != ) | |

.EN | |

are recognized. | |

Greek letters are spelled out in the desired case, as in | |

.L alpha | |

or | |

.LR GAMMA . | |

Mathematical words like | |

.LR sin , | |

.LR cos , | |

.L log | |

are made Roman automatically. | |

.IR Troff (1) | |

four-character escapes like | |

.L \e(lh | |

(\(lh) 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 | |

.I troff | |

when all else fails. | |

.SH FILES | |

.TF /sys/lib/troff/font/devutf | |

.TP | |

.B /sys/lib/troff/font/devutf | |

font descriptions for PostScript | |

.SH SOURCE | |

.B \*9/src/cmd/eqn | |

.SH "SEE ALSO" | |

.IR troff (1), | |

.IR tbl (1) | |

.br | |

J. F. Ossanna and B. W. Kernighan, | |

``Troff User's Manual''. | |

.br | |

B. W. Kernighan and L. L. Cherry, | |

``Typesetting Mathematics\(emUser's Guide'', | |

.I | |

Unix Research System Programmer's Manual, | |

Tenth Edition, Volume 2. | |

.SH BUGS | |

To embolden digits, parens, etc., | |

it is necessary to quote them, | |

as in | |

.LR bold\ "12.3" . | |

.EQ | |

delim off | |

.EN |