Dear GAP-Forum,

This is to announce bugfix number 4 for GAP 4b5. The priority of this fix
is high (except for Windows where it is very high as

** it enables the line editing under Windows **

which has been requested many times).

You should not apply this fix to any version of GAP3.

This fix corrects among other things:
1) A problem in the `ShrinkCoeffs' routine for GF(2) vectors
(shows as problem in `Gcd')
2) Problems on 64bit architectures.
3) It slightly improves the online help system.
4) A problem with `AsSSortedList' for non-kernel enumerators.
5) It fixes the problems with line editing and workspace increase
under Windows95.
6) It fixes an error with the GF(p) vector arithmetic.
7) It corrects an error in the `Size' routine for rational matrix groups.

Many thanks to:
Tom McDonough for reporting errors under 2.
Max Neunh"offer for suggesting a fix for problem 5
Cygnus software for the CYGWIN programming environment that made fix 5
possible.
Patrick Govaerts and Frank L"ubeck for reporting error 6.
Burkhard H"ofling for the Macintosh binaries.

To apply the fix you must have applied bugfixes 1 to 3 first.

Load the zoo archive 'fix4b5n4.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 fix4b5n4.zoo'. `unzoo' may ask you for permissions to overwrite
files, answer this with Y)es or A)ll.

(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'.) This will replace the
erraneous file by fixed versions.
Make sure you have write permissions when applying the fix.

This fix changes the kernel. You have to recompile by calling `make' in the
directory in which you unpacked the fix.

Windows users can find a new binary in the file win4b5f4.zoo in the
`bugfixes' directory.

Macintosh users should download the file bin4b5f4.sit in the `bugfixes'
directory which contains binaries for both 68k and PPC machines.

If you get one of these precompiled binaries you do not need to get any
precompiled binaries that would have come with earlier fixes (these old
binaries are obsolete now). Similarly, if you cannot find these binaries but
have further, newer, fixes to install check whether new binaries with these
fixes did not make the binaries of this fix obsolete.

You can remove the file 'description4' afterwards.

Alexander Hulpke, 15-Apr-99

#############################################################################
##
## These commands should run without error if the fix has been applied.
##
g:=Group((1,2,3,4,5,6,7,8),(1,2));
c:=ConjugacyClass(g,g.1);
AsSSortedList(c);;
A:=1;
f:=function() A:=[ [ Z(3), Z(3) ], [ Z(3)^0, Z(3)^0 ] ]; end;;
f();
B:=[ [ Z(3), Z(3) ], [ Z(3)^0, Z(3)^0 ] ];
AddRowVector(A[2],A[1],Z(3)^0,1,2);
AddRowVector(B[2],B[1],Z(3)^0,1,2);
if A<>B then Error("addition");fi;
P := Group([ [[ -5, 2 ], [ -12, 5 ]], [[ -1, 0 ], [ 0, -1 ]] ]);
if Size(P)<>4 then Error("size");fi;