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eqn.1 (5655B)


      1 .TH EQN 1
      2 .EQ
      3 delim $$
      4 .EN
      5 .SH NAME
      6 eqn  \- typeset mathematics
      7 .SH SYNOPSIS
      8 .B eqn
      9 [
     10 .I option ...
     11 ]
     12 [
     13 .I file ...
     14 ]
     15 .SH DESCRIPTION
     16 .I Eqn
     17 is a
     18 .MR troff (1)
     19 preprocessor
     20 for typesetting mathematics
     21 on a typesetter.
     22 Usage is almost always
     23 .IP
     24 .L
     25 eqn file ... | troff
     26 .PP
     27 If no files are specified, 
     28 .I eqn
     29 reads from the standard input.
     30 .I Eqn
     31 prepares output for the typesetter 
     32 named in the
     33 .BI -T dest
     34 option (default
     35 .BR -Tutf ;
     36 see
     37 .MR troff (1) ).
     38 When run with other preprocessor filters,
     39 .I eqn
     40 usually comes last.
     41 .PP
     42 A line beginning with
     43 .B .EQ
     44 marks the start of an equation;
     45 the end of an equation
     46 is marked by a line beginning with
     47 .BR .EN .
     48 Neither of these lines is altered,
     49 so they may be defined in macro packages
     50 to get
     51 centering, numbering, etc.
     52 It is also possible to set two characters
     53 as `delimiters';
     54 text between delimiters is also
     55 .I eqn
     56 input.
     57 Delimiters may be set to characters
     58 .I x
     59 and
     60 .I y
     61 with the option
     62 .BI -d xy
     63 or (more commonly) with
     64 .B delim
     65 .I xy
     66 between
     67 .B .EQ
     68 and
     69 .BR .EN .
     70 Left and right delimiters may be identical.
     71 (They are customarily taken to be
     72 $font L "$$" )$.
     73 Delimiters are turned off by
     74 .LR "delim off" .
     75 All text that is neither between delimiters nor between
     76 .B .EQ
     77 and
     78 .B .EN
     79 is passed through untouched.
     80 .PP
     81 Tokens within
     82 .I eqn
     83 are separated by
     84 spaces, tabs, newlines, braces, double quotes,
     85 tildes or circumflexes.
     86 Braces {} are used for grouping;
     87 generally speaking,
     88 anywhere a single character like
     89 .L x
     90 could appear, a complicated construction
     91 enclosed in braces may be used instead.
     92 Tilde
     93 .L ~
     94 represents a full space in the output,
     95 circumflex
     96 .L ^
     97 half as much.
     98 .PP
     99 .vs 13p
    100 Subscripts and superscripts are produced with the keywords
    101 .B sub
    102 and
    103 .BR sup .
    104 Thus
    105 .L "x sub i" 
    106 makes
    107 $x sub i$, 
    108 .L "a sub i sup 2"
    109 produces
    110 $a sub i sup 2$,
    111 and
    112 .L "e sup {x sup 2 + y sup 2}"
    113 gives
    114 $e sup {x sup 2 + y sup 2}$.
    115 .PP
    116 .B Over
    117 makes fractions:
    118 .L "a over b"
    119 yields $a over b$.
    120 .PP
    121 .B Sqrt
    122 produces square roots:
    123 .L "1 over sqrt {ax sup 2 +bx+c}"
    124 results in
    125 $1 over sqrt {ax sup 2 +bx+c}$ .
    126 .PP
    127 The keywords
    128 .B from
    129 and
    130 .B to
    131 introduce lower and upper
    132 limits on arbitrary things:
    133 $lim from {n -> inf} sum from 0 to n x sub i$
    134 is made with
    135 .LR "lim from {n -> inf} sum from 0 to n x sub i" .
    136 .PP
    137 Left and right brackets, braces, etc., of the right height are made with
    138 .B left
    139 and
    140 .BR right :
    141 .L "left [ x sup 2 + y sup 2 over alpha right ] ~=~1"
    142 produces
    143 $left [ x sup 2 + y sup 2 over alpha right ] ~=~1$.
    144 The
    145 .B right
    146 clause is optional.
    147 Legal characters after 
    148 .B left
    149 and
    150 .B right
    151 are braces, brackets, bars,
    152 .B c
    153 and
    154 .B f
    155 for ceiling and floor,
    156 and
    157 .B
    158 ""
    159 for nothing at all (useful for a right-side-only bracket).
    160 .PP
    161 Vertical piles of things are made with 
    162 .BR pile ,
    163 .BR lpile ,
    164 .BR cpile ,
    165 and
    166 .BR rpile :
    167 .L "pile {a above b above c}"
    168 produces
    169 $pile {a above b above c}$.
    170 There can be an arbitrary number of elements in a pile.
    171 .B lpile
    172 left-justifies,
    173 .B pile
    174 and
    175 .B cpile
    176 center, with different vertical spacing,
    177 and 
    178 .B rpile
    179 right justifies.
    180 .PP
    181 Matrices are made with
    182 .BR matrix :
    183 .L "matrix { lcol { x sub i above y sub 2 } ccol { 1 above 2 } }"
    184 produces
    185 $matrix { lcol { x sub i above y sub 2 } ccol { 1 above 2 } }$.
    186 In addition, there is
    187 .B rcol
    188 for a right-justified column.
    189 .PP
    190 .vs 12p
    191 Diacritical marks are made with
    192 .BR prime ,
    193 .BR dot ,
    194 .BR dotdot ,
    195 .BR hat ,
    196 .BR tilde ,
    197 .BR bar ,
    198 .BR under ,
    199 .BR vec ,
    200 .BR dyad ,
    201 and
    202 .BR under :
    203 .L "x sub 0 sup prime = f(t) bar + g(t) under"
    204 is
    205 $x sub 0 sup prime = f(t) bar + g(t) under$,
    206 and
    207 .L "x vec = y dyad"
    208 is
    209 $x vec = y dyad$.
    210 .PP
    211 Sizes and fonts can be changed with prefix operators
    212 .B size 
    213 .IR n ,
    214 .B size
    215 .BI ± n \f1,
    216 .BR fat ,
    217 .BR roman ,
    218 .BR italic ,
    219 .BR bold ,
    220 or
    221 .BR font
    222 .IR n .
    223 Size and fonts can be changed globally in a document by
    224 .B gsize
    225 .I n
    226 and
    227 .B gfont
    228 .IR n ,
    229 or by the command-line arguments
    230 .BI -s n
    231 and
    232 .BI -f n\f1.
    233 .PP
    234 Normally subscripts and superscripts are reduced by
    235 3 point sizes from the previous size;
    236 this may be changed by the command-line argument
    237 .BI -p n\f1.
    238 .PP
    239 Successive display arguments can be lined up.
    240 Place
    241 .B mark
    242 before the desired lineup point in the first equation;
    243 place
    244 .B lineup
    245 at the place that is to line up vertically in subsequent equations.
    246 .PP
    247 Shorthands may be defined
    248 or existing keywords redefined with
    249 .BR define :
    250 .L define
    251 .I thing
    252 .L %
    253 .I replacement
    254 .L %
    255 defines a new token called
    256 .I thing
    257 which will be replaced by
    258 .I replacement
    259 whenever it appears thereafter.
    260 The 
    261 .L %
    262 may be any character that does not occur in
    263 .LR replacement .
    264 .PP
    265 Keywords like 
    266 .L sum
    267 .EQ
    268 ( sum ),
    269 .EN
    270 .L int
    271 .EQ
    272 ( int ),
    273 .EN
    274 .L inf
    275 .EQ
    276 ( inf ),
    277 .EN
    278 and shorthands like
    279 .L >=
    280 .EQ
    281 (>=),
    282 .EN
    283 .L ->
    284 .EQ
    285 (->),
    286 .EN
    287 and
    288 .L !=
    289 .EQ
    290 ( != )
    291 .EN
    292 are recognized.
    293 Greek letters are spelled out in the desired case, as in
    294 .L alpha
    295 or
    296 .LR GAMMA .
    297 Mathematical words like
    298 .LR sin ,
    299 .LR cos ,
    300 .L log
    301 are made Roman automatically.
    302 .MR Troff (1)
    303 four-character escapes like
    304 .L \e(lh
    305 (\(lh) can be used anywhere.
    306 Strings enclosed in double quotes " "
    307 are passed through untouched;
    308 this permits keywords to be entered as text,
    309 and can be used to communicate
    310 with 
    311 .I troff
    312 when all else fails.
    313 .SH FILES
    314 .TF /sys/lib/troff/font/devutf
    315 .TP
    316 .B /sys/lib/troff/font/devutf
    317 font descriptions for PostScript
    318 .SH SOURCE
    319 .B \*9/src/cmd/eqn
    320 .SH "SEE ALSO"
    321 .IR troff (1), 
    322 .MR tbl (1)
    323 .br
    324 J. F. Ossanna and B. W. Kernighan,
    325 ``Troff User's Manual''.
    326 .br
    327 B. W. Kernighan and L. L. Cherry,
    328 ``Typesetting Mathematics\(emUser's Guide'', 
    329 .I
    330 Unix Research System Programmer's Manual,
    331 Tenth Edition, Volume 2.
    332 .SH BUGS
    333 To embolden digits, parens, etc.,
    334 it is necessary to quote them,
    335 as in 
    336 .LR bold\ "12.3" .
    337 .EQ
    338 delim off
    339 .EN