


GEQN(1)                                                   GEQN(1)


NNAAMMEE
       geqn - format equations for troff

SSYYNNOOPPSSIISS
       ggeeqqnn  [  --rrvvCCNNRR  ] [ --dd_c_c ] [ --TT_n_a_m_e ] [ --MM_d_i_r ] [ --ff_F ] [
       --ss_n ] [ --pp_n ] [ --mm_n ] [ _f_i_l_e_s...  ]

DDEESSCCRRIIPPTTIIOONN
       This manual page describes the GNU version of  eeqqnn,  which
       is part of the groff document formatting system.  eeqqnn com-
       piles descriptions  of  equations  embedded  within  ttrrooffff
       input  files  into  commands that are understood by ttrrooffff.
       Normally, it should be invoked  using  the  --ee  option  of
       ggrrooffff.  The syntax is quite compatible with Unix eqn.  The
       output of GNU eqn cannot be processed with Unix troff;  it
       must  be  processed with GNU troff.  If no files are given
       on the command line, the standard input will be  read.   A
       filename of -- will cause the standard input to be read.

       eeqqnn   searches   for   the   file  eeqqnnrrcc  using  the  path
       ..:://uu11//ggnnuu//lliibb//ggrrooffff//ttmmaacc:://uussrr//lliibb//ttmmaacc.  If it exists, eqn
       will  process  it  before  the  other input files.  The --RR
       option prevents this.

       GNU eqn does not provide the  functionality  of  neqn:  it
       does  not  support low-resolution, typewriter-like devices
       (although it may work adequately for very simple input).

OOPPTTIIOONNSS
       --CC     Recognize ..EEQQ and ..EENN even when followed by a char-
              acter other than space or newline.

       --NN     Don't   allow  newlines  within  delimiters.   This
              option allows eeqqnn to recover  better  from  missing
              closing delimiters.

       --vv     Print the version number.

       --rr     Only one size reduction.

       --mm_n    The  minimum  point-size is _n.  eqn will not reduce
              the size of subscripts or superscripts to a smaller
              size than _n.

       --TT_n_a_m_e The  output is for device _n_a_m_e.  The only effect of
              this is to define a macro _n_a_m_e with a value  of  11.
              Typically  eeqqnnrrcc  will  use this to provide defini-
              tions  appropriate  for  the  output  device.   The
              default output device is ppss.

       --MM_d_i_r  Search  _d_i_r  for  eeqqnnrrcc before the default directo-
              ries.

       --RR     Don't load eeqqnnrrcc.



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GEQN(1)                                                   GEQN(1)


       --ff_F    This is equivalent to a ggffoonntt _F command.

       --ss_n    This is equivalent  to  a  ggssiizzee _n  command.   This
              option  is deprecated.  eqn will normally set equa-
              tions at whatever the current point  size  is  when
              the equation is encountered.

       --pp_n    This  says  that subscripts and superscripts should
              be _n points  smaller  than  the  surrounding  text.
              This option is deprecated.  Normally eqn makes sets
              subscripts and superscripts at 70% of the  size  of
              the surrounding text.

UUSSAAGGEE
       Only  the  differences  between  GNU  eqn and Unix eqn are
       described here.

       Most of the new features of GNU  eqn  are  based  on  TeX.
       There  are  some references to the differences between TeX
       and GNU eqn below; these may safely be ignored if  you  do
       not know TeX.

   AAuuttoommaattiicc ssppaacciinngg
       eeqqnn  gives  each  component  of  an  equation  a type, and
       adjusts the spacing between components  using  that  type.
       Possible types are:

       ordinary     an ordinary character such as 1 or _x;
                                             _
       operator     a large operator such as _>;

       binary       a binary operator such as +;

       relation     a relation such as =;

       opening      a opening bracket such as (;

       closing      a closing bracket such as );

       punctuation  a punctutation character such as ,;

       inner        a subformula contained within brackets;

       suppress     spacing  that  suppresses  automatic  spacing
                    adjustment.

       Components of an equation get a type in one of two ways.

       ttyyppee _t _e
              This yields an equation component that  contains  _e
              but  that  has  type _t, where _t is one of the types
              mentioned above.  For example, ttiimmeess is defined as

                     ttyyppee ""bbiinnaarryy"" \\((mmuu



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GEQN(1)                                                   GEQN(1)


              The name of the type doesn't have to be quoted, but
              quoting protects from macro expansion.

       cchhaarrttyyppee _t _t_e_x_t
              Unquoted  groups  of  characters  are split up into
              individual characters, and the type of each charac-
              ter  is  looked  up;  this changes the type that is
              stored for each character; it says that the charac-
              ters in _t_e_x_t from now on have type _t.  For example,

                     cchhaarrttyyppee ""ppuunnccttuuaattiioonn"" ..,,;;::

              would make the characters ..,,;;:: have  type  punctua-
              tion  whenever  they  subsequently  appeared  in an
              equation.  The type _t can also be lleetttteerr or  ddiiggiitt;
              in  these  cases  cchhaarrttyyppee changes the font type of
              the characters.  See the Fonts subsection.

   NNeeww pprriimmiittiivveess
       _e_1 ssmmaalllloovveerr _e_2
              This is similar to oovveerr; ssmmaalllloovveerr reduces the size
              of  _e_1  and  _e_2;  it  also puts less vertical space
              between _e_1 or _e_2 and the fraction  bar.   The  oovveerr
              primitive corresponds to the TeX \\oovveerr primitive in
              display styles; ssmmaalllloovveerr corresponds to  \\oovveerr  in
              non-display styles.

       vvcceenntteerr _e
              This vertically centers _e about the math axis.  The
              math axis is  the  vertical  position  about  which
              characters such as + and - are centered; also it is
              the vertical position used for  the  bar  of  frac-
              tions.  For example, ssuumm is defined as

                     {{ ttyyppee ""ooppeerraattoorr"" vvcceenntteerr ssiizzee ++55 \\((**SS }}

       _e_1 aacccceenntt _e_2
              This  sets  _e_2 as an accent over _e_1.  _e_2 is assumed
              to be at the correct height for a lowercase letter;
              _e_2  will be moved down according if _e_1 is taller or
              shorter than a lowercase letter.  For example,  hhaatt
              is defined as

                     aacccceenntt {{ ""^^"" }}

              ddoottddoott,  ddoott,  ttiillddee, vveecc and ddyyaadd are also defined
              using the aacccceenntt primitive.

       _e_1 uuaacccceenntt _e_2
              This sets _e_2 as an accent under _e_1.  _e_2 is  assumed
              to be at the correct height for a character without
              a descender; _e_2 will be moved  down  if  _e_1  has  a
              descender.   uuttiillddee is pre-defined using uuaacccceenntt as
              a tilde accent below the baseline.



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GEQN(1)                                                   GEQN(1)


       sspplliitt ""_t_e_x_t""
              This has the same effect as simply

                     _t_e_x_t

              but _t_e_x_t is not subject to macro expansion  because
              it is quoted; _t_e_x_t will be split up and the spacing
              between individual characters will be adjusted.

       nnoosspplliitt _t_e_x_t
              This has the same effect as

                     ""_t_e_x_t""

              but because _t_e_x_t is not quoted it will  be  subject
              to  macro  expansion; _t_e_x_t will not be split up and
              the spacing between individual characters will  not
              be adjusted.

       _e oopppprriimmee
              This is a variant of pprriimmee that acts as an operator
              on _e.  It produces a different result from pprriimmee in
              a  case such as AA oopppprriimmee ssuubb 11: with oopppprriimmee the 11
              will be tucked under the prime as  a  subscript  to
              the  AA (as is conventional in mathematical typeset-
              ting), whereas with pprriimmee the 11 will be a subscript
              to  the prime character.  The precedence of oopppprriimmee
              is the same as that of  bbaarr  and  uunnddeerr,  which  is
              higher  than  that  of everything except aacccceenntt and
              uuaacccceenntt.  In unquoted text a  ''  that  is  not  the
              first character will be treated like oopppprriimmee.

       ssppeecciiaall _t_e_x_t _e
              This  constructs  a  new  object  from  _e  using  a
              ggttrrooffff(1) macro named  _t_e_x_t.   When  the  macro  is
              called,  the  string 00ss will contain the output for
              _e, and the number registers 00ww, 00hh, 00dd, 00sskkeerrnn  and
              00sskkeeww  will  contain the width, height, depth, sub-
              script kern, and skew of _e.  (The _s_u_b_s_c_r_i_p_t _k_e_r_n of
              an  object says how much a subscript on that object
              should be tucked in; the _s_k_e_w of an object says how
              far  to  the  right  of the center of the object an
              accent over the  object  should  be  placed.)   The
              macro  must  modify  00ss  so that it will output the
              desired result  with  its  origin  at  the  current
              point, and increase the current horizontal position
              by the width of the object.  The  number  registers
              must  also  be  modified so that they correspond to
              the result.

              For example, suppose you wanted  a  construct  that
              `cancels'  an expression by drawing a diagonal line
              through it.




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GEQN(1)                                                   GEQN(1)


                     ..EEQQ
                     ddeeffiinnee ccaanncceell ''ssppeecciiaall CCaa''
                     ..EENN
                     ..ddee CCaa
                     ..ddss 00ss \\ZZ''\\\\**((00ss''\\vv''\\\\nn((00dduu''\\DD''ll \\\\nn((00wwuu --\\\\nn((00hhuu--\\\\nn((00dduu''\\vv''\\\\nn((00hhuu''
                     ....

              Then  you  could  cancel  an  expression   _e   with
              ccaanncceell {{ _e }}

              Here's  a  more  complicated construct that draws a
              box round an expression:

                     ..EEQQ
                     ddeeffiinnee bbooxx ''ssppeecciiaall BBxx''
                     ..EENN
                     ..ddee BBxx
                     ..ddss 00ss \\ZZ''\\hh''11nn''\\\\**((00ss''\\
                     \\ZZ''\\vv''\\\\nn((00dduu++11nn''\\DD''ll \\\\nn((00wwuu++22nn 00''\\DD''ll 00 --\\\\nn((00hhuu--\\\\nn((00dduu--22nn''\\
                     \\DD''ll --\\\\nn((00wwuu--22nn 00''\\DD''ll 00 \\\\nn((00hhuu++\\\\nn((00dduu++22nn''''\\hh''\\\\nn((00wwuu++22nn''
                     ..nnrr 00ww ++22nn
                     ..nnrr 00dd ++11nn
                     ..nnrr 00hh ++11nn
                     ....

   CCuussttoommiizzaattiioonn
       The appearance of equations is controlled by a large  num-
       ber of parameters. These can be set using the sseett command.

       sseett _p _n
              This sets parameter _p to value _n _; _n is an integer.
              For example,

                     sseett xx__hheeiigghhtt 4455

              says  that  eeqqnn  should  assume an x height of 0.45
              ems.

              Possible parameters are as follows.  Values are  in
              units  of  hundredths  of  an  em  unless otherwise
              stated.  These  descriptions  are  intended  to  be
              expository rather than definitive.

              mmiinniimmuumm__ssiizzee            eeqqnn  will  not set anything
                                      at  a  smaller   point-size
                                      than this.  The value is in
                                      points.

              ffaatt__ooffffsseett              The ffaatt primitive emboldens
                                      an equation by overprinting
                                      two copies of the  equation
                                      horizontally offset by this
                                      amount.




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GEQN(1)                                                   GEQN(1)


              oovveerr__hhaanngg               A  fraction  bar  will   be
                                      longer by twice this amount
                                      than  the  maximum  of  the
                                      widths of the numerator and
                                      denominator;    in    other
                                      words, it will overhang the
                                      numerator  and  denominator
                                      by at least this amount.

              aacccceenntt__wwiiddtthh            When   bbaarr   or   uunnddeerr  is
                                      applied to a single charac-
                                      ter,  the line will be this
                                      long.   Normally,  bbaarr   or
                                      uunnddeerr produces a line whose
                                      length is the width of  the
                                      object to which it applies;
                                      in the  case  of  a  single
                                      character,  this  tends  to
                                      produce a line  that  looks
                                      too long.

              ddeelliimmiitteerr__ffaaccttoorr        Extensible  delimiters pro-
                                      duced  with  the  lleefftt  and
                                      rriigghhtt  primitives will have
                                      a combined height and depth
                                      of at least this many thou-
                                      sandths of twice the  maxi-
                                      mum  amount  by  which  the
                                      sub-equation    that    the
                                      delimiters  enclose extends
                                      away from the axis.

              ddeelliimmiitteerr__sshhoorrttffaallll     Extensible delimiters  pro-
                                      duced  with  the  lleefftt  and
                                      rriigghhtt primitives will  have
                                      a combined height and depth
                                      not less than  the  differ-
                                      ence  of  twice the maximum
                                      amount by  which  the  sub-
                                      equation  that  the  delim-
                                      iters enclose extends  away
                                      from   the  axis  and  this
                                      amount.

              nnuullll__ddeelliimmiitteerr__ssppaaccee    This much horizontal  space
                                      is inserted on each side of
                                      a fraction.

              ssccrriipptt__ssppaaccee            The width of subscripts and
                                      superscripts  is  increased
                                      by this amount.

              tthhiinn__ssppaaccee              This  amount  of  space  is
                                      automatically      inserted



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GEQN(1)                                                   GEQN(1)


                                      after  punctuation  charac-
                                      ters.

              mmeeddiiuumm__ssppaaccee            This  amount  of  space  is
                                      automatically  inserted  on
                                      either side of binary oper-
                                      ators.

              tthhiicckk__ssppaaccee             This  amount  of  space  is
                                      automatically  inserted  on
                                      either side of relations.

              xx__hheeiigghhtt                The  height  of   lowercase
                                      letters  without  ascenders
                                      such as x.

              aaxxiiss__hheeiigghhtt             The height above the  base-
                                      line of the center of char-
                                      acters such as + and -.  It
                                      is   important   that  this
                                      value is  correct  for  the
                                      font you are using.

              ddeeffaauulltt__rruullee__tthhiicckknneessss  This   should  set  to  the
                                      thickness of the \\((rruu char-
                                      acter,  or the thickness of
                                      horizontal  lines  produced
                                      with    the    \\DD    escape
                                      sequence.

              nnuumm11                    The oovveerr command will shift
                                      up   the  numerator  by  at
                                      least this amount.

              nnuumm22                    The ssmmaalllloovveerr command  will
                                      shift  up  the numerator by
                                      at least this amount.

              ddeennoomm11                  The oovveerr command will shift
                                      down  the denominator by at
                                      least this amount.

              ddeennoomm22                  The ssmmaalllloovveerr command  will
                                      shift  down the denominator
                                      by at least this amount.

              ssuupp11                    Normally superscripts  will
                                      be  shifted  up by at least
                                      this amount.

              ssuupp22                    Superscripts within  super-
                                      scripts  or upper limits or
                                      numerators   of   ssmmaalllloovveerr
                                      fractions  will  be shifted



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GEQN(1)                                                   GEQN(1)


                                      up by at least this amount.
                                      This  is  usually less than
                                      sup1.

              ssuupp33                    Superscripts within denomi-
                                      nators  or  square roots or
                                      subscripts or lower  limits
                                      will  be  shifted  up by at
                                      least this amount.  This is
                                      usually less than sup2.

              ssuubb11                    Subscripts will normally be
                                      shifted down  by  at  least
                                      this amount.

              ssuubb22                    When  there  is both a sub-
                                      script and  a  superscript,
                                      the   subscript   will   be
                                      shifted down  by  at  least
                                      this amount.

              ssuupp__ddrroopp                The  baseline  of  a super-
                                      script will be no more than
                                      this  much amount below the
                                      top of the object on  which
                                      the superscript is set.

              ssuubb__ddrroopp                The baseline of a subscript
                                      will be at least this  much
                                      below  the  bottom  of  the
                                      object on  which  the  sub-
                                      script is set.

              bbiigg__oopp__ssppaacciinngg11         The  baseline  of  an upper
                                      limit will be at least this
                                      much  above  the top of the
                                      object on which  the  limit
                                      is set.

              bbiigg__oopp__ssppaacciinngg22         The  baseline  of  a  lower
                                      limit will be at least this
                                      much  below  the  bottom of
                                      the  object  on  which  the
                                      limit is set.

              bbiigg__oopp__ssppaacciinngg33         The   bottom  of  an  upper
                                      limit will be at least this
                                      much  above  the top of the
                                      object on which  the  limit
                                      is set.

              bbiigg__oopp__ssppaacciinngg44         The  top  of  a lower limit
                                      will be at least this  much
                                      below  the  bottom  of  the



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GEQN(1)                                                   GEQN(1)


                                      object on which  the  limit
                                      is set.

              bbiigg__oopp__ssppaacciinngg55         This  much  vertical  space
                                      will  be  added  above  and
                                      below limits.

              bbaasseelliinnee__sseepp            The  baselines  of the rows
                                      in a pile  or  matrix  will
                                      normally be this far apart.
                                      In most cases  this  should
                                      be equal to the sum of nnuumm11
                                      and ddeennoomm11.

              sshhiifftt__ddoowwnn              The  midpoint  between  the
                                      top baseline and the bottom
                                      baseline  in  a  matrix  or
                                      pile  will  be shifted down
                                      by this much from the axis.
                                      In  most  cases this should
                                      be equal to aaxxiiss__hheeiigghhtt.

              ccoolluummnn__sseepp              This  much  space  will  be
                                      added  between columns in a
                                      matrix.

              mmaattrriixx__ssiiddee__sseepp         This  much  space  will  be
                                      added  at  each  side  of a
                                      matrix.

              ddrraaww__lliinneess              If this is non-zero,  lines
                                      will  be drawn using the \\DD
                                      escape   sequence,   rather
                                      than  with  the  \\ll  escape
                                      sequence and the \\((rruu char-
                                      acter.

              bbooddyy__hheeiigghhtt             The  amount  by  which  the
                                      height  of   the   equation
                                      exceeds  this will be added
                                      as extra space  before  the
                                      line  containing  the equa-
                                      tion   (using   \\xx.)    The
                                      default value is 85.

              bbooddyy__ddeepptthh              The  amount  by  which  the
                                      depth   of   the   equation
                                      exceeds  this will be added
                                      as extra  space  after  the
                                      line  containing  the equa-
                                      tion   (using   \\xx.)    The
                                      default value is 35.

              nnrrooffff                   If  this  is non-zero, then



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GEQN(1)                                                   GEQN(1)


                                      nnddeeffiinnee  will  behave  like
                                      ddeeffiinnee  and ttddeeffiinnee will be
                                      ignored, otherwise  ttddeeffiinnee
                                      will behave like ddeeffiinnee and
                                      nnddeeffiinnee  will  be  ignored.
                                      The   default  value  is  0
                                      (This is typically  changed
                                      to  1 by the eeqqnnrrcc file for
                                      the   aasscciiii   and    llaattiinn11
                                      devices.)

              A  more  precise description of the role of many of
              these parameters can be  found  in  Appendix  H  of
              _T_h_e _T_e_X_b_o_o_k.

   MMaaccrrooss
       Macros can take arguments.  In a macro body, $$_n where _n is
       between 1 and 9, will be replaced by the _n_-_t_h argument  if
       the  macro  is  called  with arguments; if there are fewer
       than _n arguments, it will be replaced by nothing.  A  word
       containing  a  left parenthesis where the part of the word
       before the left parenthesis has  been  defined  using  the
       ddeeffiinnee  command  will  be  recognized as a macro call with
       arguments; characters following the left parenthesis up to
       a  matching  right  parenthesis  will be treated as comma-
       separated arguments; commas inside nested  parentheses  do
       not terminate an argument.

       ssddeeffiinnee _n_a_m_e _X _a_n_y_t_h_i_n_g _X
              This  is like the ddeeffiinnee command, but _n_a_m_e will not
              be recognized if called with arguments.

       iinncclluuddee ""_f_i_l_e""
              Include the contents of _f_i_l_e.  Lines of _f_i_l_e begin-
              ning with ..EEQQ or ..EENN will be ignored.

       iiffddeeff _n_a_m_e _X _a_n_y_t_h_i_n_g _X
              If  _n_a_m_e  has  been  defined by ddeeffiinnee (or has been
              automatically defined because _n_a_m_e  is  the  output
              device)  process  _a_n_y_t_h_i_n_g;  otherwise  ignore _a_n_y_-
              _t_h_i_n_g.  _X can be any  character  not  appearing  in
              _a_n_y_t_h_i_n_g.

   FFoonnttss
       eeqqnn  normally  uses at least two fonts to set an equation:
       an italic font for letters, and a roman  font  for  every-
       thing  else.   The existing ggffoonntt command changes the font
       that is used as the italic font.  By default  this  is  II.
       The  font  that  is  used as the roman font can be changed
       using the new ggrrffoonntt command.

       ggrrffoonntt _f
              Set the roman font to _f.




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GEQN(1)                                                   GEQN(1)


       The iittaalliicc primitive uses the current italic font  set  by
       ggffoonntt; the rroommaann primitive uses the current roman font set
       by ggrrffoonntt.  There is also  a  new  ggbbffoonntt  command,  which
       changes  the font used by the bboolldd primitive.  If you only
       use the rroommaann, iittaalliicc and bboolldd primitives to changes fonts
       within  an  equation, you can change all the fonts used by
       your equations just by using ggffoonntt, ggrrffoonntt and ggbbffoonntt com-
       mands.

       You  can  control  which characters are treated as letters
       (and therefore set in italics) by using the cchhaarrttyyppee  com-
       mand described above.  A type of lleetttteerr will cause a char-
       acter to be set in italic type.   A  type  of  ddiiggiitt  will
       cause a character to be set in roman type.

FFIILLEESS
       //uu11//ggnnuu//lliibb//ggrrooffff//ttmmaacc//eeqqnnrrcc
              Initialization file.

BBUUGGSS
       Inline  equations  will  be  set at the point size that is
       current at the beginning of the input line.

SSEEEE AALLSSOO
       ggrrooffff(1), ggttrrooffff(1), ggrrooffff__ffoonntt(5), _T_h_e _T_e_X_b_o_o_k
































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