32v 1m eqn

NAME

    eqn, neqn, checkeq  -  typeset mathematics

SYNOPSIS

    eqn [ -dxy ] [ -pn ] [ -sn ] [ -fn ] [ file ] ...
    checkeq [ file ] ...

DESCRIPTION

    _E_q_n is a troff(1) preprocessor for typesetting mathematics
    on a Graphic Systems phototypesetter, _n_e_q_n 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 _e_q_n input.  Delimiters may be set to characters _x
    and _y with the command-line argument -d_x_y or (more commonly)
    with `delim _x_y' 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 _c_h_e_c_k_e_q reports missing or unbalanced delimiters
    and .EQ/.EN pairs.

    Tokens within _e_q_n 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 _s_u_b _i makes $x sub i$, _a _s_u_b _i _s_u_p _2
    produces $a sub i sup 2$, and _e _s_u_p {_x _s_u_p _2 + _y _s_u_p _2}
    gives $e sup {x sup 2 + y sup 2}$.

    Fractions are made with over: _a _o_v_e_r _b yields $a over b$.

    sqrt makes square roots: _1 _o_v_e_r _s_q_r_t {_a_x _s_u_p _2 +_b_x+_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 _l_i_m _f_r_o_m {_n-> _i_n_f } _s_u_m _f_r_o_m _0 _t_o _n _x _s_u_b _i.

    Left and right brackets, braces, etc., of the right height
    are made with left and right: _l_e_f_t [ _x _s_u_p _2 + _y _s_u_p _2 _o_v_e_r
    _a_l_p_h_a _r_i_g_h_t ] ~=~_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: _p_i_l_e {_a _a_b_o_v_e _b _a_b_o_v_e _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: _m_a_t_r_i_x { _l_c_o_l { _x _s_u_b _i _a_b_o_v_e
    _y _s_u_b _2 } _c_c_o_l { _1 _a_b_o_v_e _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 _d_o_t = _f(_t) _b_a_r is $x dot = f(t)
    bar$, _y _d_o_t_d_o_t _b_a_r ~=~ _n _u_n_d_e_r is $y dotdot bar ~=~ n
    under$, and _x _v_e_c ~=~ _y _d_y_a_d 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 glo-
    bally in a document by gsize _n and gfont _n, or by the
    command-line arguments -s_n and -f_n.

    Normally subscripts and superscripts are reduced by 3 point
    sizes from the previous size; this may be changed by the
    command-line argument -p_n.

    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: _d_e_f_i_n_e _t_h_i_n_g % _r_e_p_l_a_c_e_m_e_n_t % defines a new
    token called _t_h_i_n_g which will be replaced by _r_e_p_l_a_c_e_m_e_n_t
    whenever it appears thereafter.  The % may be any character
    that does not occur in _r_e_p_l_a_c_e_m_e_n_t.

    Keywords like _s_u_m ( sum ) _i_n_t ( int ) _i_n_f ( inf ) and short-
    hands like >= (>=) -> (->), and != ( != ) are recognized.
    Greek letters are spelled out in the desired case, as in
    _a_l_p_h_a or _G_A_M_M_A. Mathematical words like sin, cos, log are
    made Roman automatically.  _T_r_o_f_f(1) four-character escapes
    like \(bs () can be used anywhere.  Strings enclosed in dou-
    ble quotes "..." are passed through untouched; this permits
    keywords to be entered as text, and can be used to communi-
    cate with _t_r_o_f_f when all else fails.

SEE ALSO

    troff(1), tbl(1), ms(7), eqnchar(7)
    B. W. Kernighan and L. L. Cherry, _T_y_p_e_s_e_t_t_i_n_g _M_a_t_h_e_m_a_t_i_c_s-
    _U_s_e_r'_s _G_u_i_d_e
    J. F. Ossanna, _N_R_O_F_F/_T_R_O_F_F _U_s_e_r'_s _M_a_n_u_a_l

BUGS

    To embolden digits, parens, etc., it is necessary to quote
    them, as in `bold "12.3"'.