This mail contains a bugfix for a serious problem in GAP 3.4.3.
You should apply this bugfix soon.
The problem is in 'MTXOps.EquivalenceTest', and causes it to fail.

VERSION

GAP/lib 3.4.3.0

PRIORITY

The problem is a serious problem, because it may cause a computation to
fail. Thus the bugfix has medium priority, and we recommend that you
apply it soon.

HOW TO APPLY

Go to the GAP directory (the directory with the 'lib/' subdirectory),
name this mail 'fix22lib.dif', and issue the command:

patch -p0 < fix22lib.dif

If 'patch' writes "I can't seem to find a patch in there" try 'patch -v'.
If 'patch -v' gives an error message or reports a version older than 2.1,
get 2.1 from 'ftp://FTP.Math.RWTH-Aachen.DE/pub/gap/utils/patch2_1.zoo'.

This fix changes only the library.
Thus you need not recompile the GAP kernel.

DESCRIPTION

'MTXOps.EquivalenceTest' fails and signals

Error, Length: <list> must be a list at
until Length( base ) = module_descr1[3]
or line > enum.numberLines ... in
MTXOps.EquivalenceTest( d1, d2 ) called from
main loop

CORRECT BEHAVIOUR

gap> d1:= [ [ [ [ Z(2)^0, Z(2)^0 ], [ 0*Z(2), Z(2)^0 ] ],
>           [ [ 0*Z(2), Z(2)^0 ], [ Z(2)^0, 0*Z(2) ] ] ], GF(2), 2 ];;
gap> d2:= [ [ [ [ Z(2)^0, Z(2)^0 ], [ 0*Z(2), Z(2)^0 ] ],
>           [ [ Z(2)^0, 0*Z(2) ], [ Z(2)^0, Z(2)^0 ] ] ], GF(2), 2 ];;
gap> MTXOps.EquivalenceTest( d1, d2 );
rec(
  areequivalent := true,
  transformationMatrix := [ [ Z(2)^0, Z(2)^0 ], [ 0*Z(2), Z(2)^0 ] ] )

COMMENT

'MTXOps.EquivalenceTest' calls 'SpinUpStandard', which returns a record.
This record was used in the following computations, instead of its
'vectors' component.

DIFFS

Prereq: 3.20.1.5
--- lib/matgrp.g        Thu Sep  5 13:50:11 1996
+++ lib/matgrp.g        Fri Sep 13 13:57:48 1996
@@ -2,7 +2,7 @@
 ##
 #A  matgrp.g                    GAP library                  Martin Schoenert
 ##
-#A  @(#)$Id: 1.html,v 1.2 2004/04/21 15:03:10 felsch Exp $
+#A  @(#)$Id: 1.html,v 1.2 2004/04/21 15:03:10 felsch Exp $
 ##
 #Y  Copyright 1990-1992,  Lehrstuhl D fuer Mathematik,  RWTH Aachen,  Germany
 ##
@@ -22,6 +22,10 @@
 ##  matrices, which means the algebra generated by the identity matrix.)
 ##
 #H  $Log: 1.html,v $
 #H  Revision 1.2  2004/04/21 15:03:10  felsch
 #H  Corrected links in the Forum Archive pages.   VF
 #H
 #H  Revision 1.1.1.1  2004/04/20 13:39:30  felsch
 #H  The final GAP-Forum archive until 2003.
 #H
 #H  Revision 1.4  2003/06/12 19:20:34  gap
 #H  Further update. AH
 #H
 #H  Revision 1.3  1997/08/15 11:19:38  gap
 #H  New forum setup. AH
 #H
 #H  Revision 1.2  1997/04/24 15:33:16  gap
 #H  These files were replaced by the versions in WWW. The content is basically the
 #H  same but the formatting has been much more friendly towards the HTML-Converter.
 #H  AH
 #H
 #H  Revision 1.1  1996/10/30 13:07:07  gap
 #H  added forum archive and translation files.
 #H
+#H  Revision 3.20.1.6  1996/09/13 11:56:50  sam
+#H  'MTXOps.EquivalenceTest' needs only the 'vectors' component of the
+#H  record returned by 'SpinUpStandard'
+#H
 #H  Revision 3.20.1.5  1995/11/22  12:12:47  sam
 #H  made MeatAxe functions independent of MatGroupOps
 #H
@@ -1701,7 +1705,8 @@
     enum := LineEnumeration( ns1 );
     line := 1;
     repeat
-        base := SpinUpStandard( [ enum.line( line ) ], module_descr1[1] );
+        base := SpinUpStandard( [ enum.line( line ) ],
+                                module_descr1[1] ).vectors;
         line := line + 1;
     until Length( base ) = module_descr1[3] or line > enum.numberLines;

@@ -1712,7 +1717,8 @@

repeat

-            base := SpinUpStandard( [ enum.line( line ) ], module_descr2[1] );
+            base := SpinUpStandard( [ enum.line( line ) ],
+                                    module_descr2[1] ).vectors;
             line := line + 1;

             if Length( base ) = module_descr2[3] then
END OF  fix22lib.dif ________________________________________________________