Dear Forum,

This is to announce bugfix number 8 for GAP 4.2. The priority of this fix
is high.

You should not apply this fix to any version of GAP 3, nor to any version of
GAP 4.1.

This fix corrects:

1) A problem with `RepresentativeAction' for the action on tuples,
where the two tuples have different lengths
(and thus the result should be `fail').
2) A (rare) problem when computing the character table of a group.
3) A bug in the function `BaumClausenInfo' that caused wrong results
of `IrreducibleRepresentations' and the computation of irreducible
characters in some cases.
4) A bug in the calculation of factor groups if the group is trivial
5) A missing `Enumerator' method for double cosets
6) A problem with accessing the trivial subgroup from a table of marks
via RepresentativeTomByGenerators.
7) A problem with exponent calculations with respect to a tail of a
permutation pcgs.
8) A problem with `Order' for matrices in characteristic zero.

Errors 1), 3),6) and 7) may cause wrong results or error messages.
Errors 2), 4), 5), and 8) may lead to an error message.

Many thanks to:
Leonard Soicher for reporting error 1),
Harald Meyer for reporting error 2).
Peter Cameron for reporting error 4).
Michael Hatley for reporting error 5).
Klaus Lux for reporting error 6).
Peter Mueller for reporting error 7).

Installing the bugfix.
======================

Load the zoo archive `fix4r2n8.zoo' from the bugfixes web page
http://www-gap.dcs.st-and.ac.uk/~gap/Info4/bugfixes.html
Alternatively you can find this file in the `bugfixes' directory of the
GAP4 ftp distribution.

Unpack the file in the home directory of your GAP distribution (the
directory containing the `lib' and `grp' directories) using `unzoo -x
fix4r2n8.zoo'. `unzoo' may ask you for permissions to overwrite files,
answer this with Y)es or A)ll. This will replace the erroneous files by
fixed versions.

(On a PC or a Mac you will have to copy `unzoo' in the same directory and
enter the argument line after the call to `unzoo'.)
Make sure you have write permissions when applying the fix.

You can remove the file `description8' afterwards.

After installing the bugfix you can test whether
the bugfix has been applied correctly by starting GAP from the `gap4r2'
directory and issuing

gap> ReadTest("tst/bugfix.tst");
+ bugfixes test
+ GAP4stones: 163
true

(The output should be like this if the bugfixes have been installed
correctly. The number of GAP4stones may vary according to your system.)

Running this test is not a necessary part of installing a bug fix, but only
serves as a confirmation that everything went well. The test might run for
a long time and GAP will not output information while running. Note that it
is not possible to run the test twice without restarting GAP and that an
interruption of the test with CTRL-C will produce lots of (harmless) error
messages.

Alexander Hulpke, June 7, 2001