EQN(1)                                                                  EQN(1)


NAME
     eqn - format mathematical text for troff

SYNOPSIS
     eqn [ -d xx ] [ -p n ] [ -s n ] [ -f n ] [ -Ttty_type ] [ file(s) ]

DESCRIPTION
     eqn is a troff(1) preprocessor for typesetting mathematical text on a
     phototypesetter.  Normal usage is:

          eqn [option(s)] file(s) | troff [option(s)] | [typesetter]

     If you do not specify files (or if you specify - as the last argument),
     eqn reads the standard input.  eqn prepares output for the typesetter you
     name in the -T option. Currently supported devices are -Taps (Autologic
     APS-5), and -Ti10 (Imagen Imprint-10).  The default is -Taps.

     A line beginning with .EQ marks the start of an equation; the end of an
     equation is marked by a line beginning with .EN.  troff does not alter
     these lines, so they may be defined in macro packages to get centering,
     numbering, etc.  You may also name two characters as delimiters; eqn
     treats subsequent text between delimiters as input.  Delimiters may be
     set to characters x and x with the command-line argument -d xx or (more
     commonly) with delim xx between .EQ and .EN.  The left and right
     delimiters may be the same character; the dollar sign is often used as
     such a delimiter.  Turn delimiters off with delim off.  eqn touches only
     text that is between delimiters or between .EQ and .EN.

     Set apart keyword recognized by eqn with spaces, tabs, new-lines, braces,
     double quotes, tildes, and circumflexes.  Use braces {} for grouping;
     generally speaking, anywhere you can use single character such as x, you
     may use a complicated construction enclosed in braces instead.  Tilde (~)
     represents a full space in the output, circumflex (^) half as much.

     Subscripts and superscripts are produced with the keywords sub and sup.
     Fractions are made with over. sqrt makes square roots.

     The keywords from and to introduce lower and upper limits.  Left and
     right brackets, braces, etc., of the right height are made with left and
     right.  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, but a right thing must have a matching left thing.

     Vertical piles of things are made with pile, lpile, cpile, and rpile.
     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. In addition, there is rcol for
     a right-justified column.


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

     You may change point sizes and fonts with size n or size+n, roman,
     italic, bold, and font n. You may change point sizes and fonts 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; you may change this with the command-line argument -pn.

     You can line up successive display arguments. 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.

     You may define shorthands or redefine existing keywords with define:

          define thing % replacement %

     defines a new token called thing that is 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 or GAMMA. Mathematical words such as sin, cos, and log are made
     Roman automatically. troff(1) four-character escapes such as \(dd, which
     produces the double dagger, 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 troff(1) when
     all else fails. Full details are given in the REFERENCE cited below.

SEE ALSO
     mmt(1), mvt(1), neqn(1), nroff(1), tbl(1), troff(1), eqnchar(5), mm(5),
     and mv(5).

     "The Preprocessor eqn" in the User's Guide.

BUGS
     To embolden digits, parentheses, etc., it is necessary to quote them, as
     in bold "12.3". When you use eqn with the mm macro package, displayed
     equations must appear only inside displays.

     See also BUGS under troff(1).


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