What is XGAP?
-------------

XGAP is a graphical user interface for GAP, it extends the GAP library
with functions  dealing with graphic sheets  and objects.  Using these
functions it also supplies a graphical interface for investigating the
subgroup lattice of a  group, giving you  easy access to the low index
subgroups,  prime quotient  and  Reidemeister-Schreier algorithms  and
many other GAP functions for groups and subgroups.   At the moment the
only supported window system is X-Windows X11R5 (and higher), however,
programs using the XGAP library functions will  run on other platforms
as soon as XGAP is  available on these.   We plan to release a Windows
3.11 or Windows 95 version in the near future.

XGAP will also run under SUN's OpenWindow.  It doesn't however compile
under OpenWindow.  If any OpenWindow guru can fix this, please send me
a patch.

Where to get XGAP?
------------------

You can get XGAP from  "ftp.math.rwth-aachen.de", the source code  and
binaries are in the directory "/pub/incoming":

  xgap1r3.zoo (333917 Bytes) - this archive contains the C source code
      and the GAP library files necessary to compile and run XGAP.

  xgap1r3-dec-alpha-osf1-x11r5.zoo (820751 Bytes) - this archive
      contains the executable for a DECalpha running OSF1 and X11R5.

  xgap1r3-dec-mips-ultrix42-x11r5.zoo (434616 Bytes) - this archive
      contains the executable for a DECstation running Ultrix 4.2 and
      X11R5.

  xgap1r3-hp-hppa1.1-hpux9-x11r5.zoo (410380 Bytes) - this archive
      contains the executable for a HP9000/700 running HPUX9 and
      X11R5.

  xgap1r3-sun-sparc-sunos412-x11r5.zoo (464671 Bytes) - this archive
      contains the executable for a SUN SPARCstation running SunOS
      4.1.2 and X11R5, I assume that it also works under OpenWindows,
      any feedback welcome.

How to compile XGAP?
--------------------

Instructions can be found in the file "gap3r4p?/pkg/xgap/INSTALL.x11".
You need at least a CC compiler, X11R5 & Athena Widgets, and a running
version of GAP 3.4.
