[GAP Forum] Unexpected behaviour on StructureDescription()

[Stefan Kohl]

Dear Forum,

Nilo de Roock wrote:

> The command
>
> StructureDescription(DirectProduct(CyclicGroup(5),SymmetricGroup(4)));
> 
> generated the following response:
> 
> gap> StructureDescription(DirectProduct(CyclicGroup(5),SymmetricGroup(4)));
> #I  default `IsGeneratorsOfMagmaWithInverses' method returns `true' for
> [ Tuple( [ f1, () ] ) ]

This is due to a problem in a method in the package CRISP.
In the meantime the author of this package has fixed this bug.

Remedies are:

- upgrade to CRISP 1.3, or

- use

   StructureDescription(DirectProduct(CyclicGroup(IsPermGroup,5),
                                      SymmetricGroup(4))); or

   StructureDescription(DirectProduct(CyclicGroup(5),
                                      SymmetricGroup(IsPcGroup,4)));
   instead or

- start GAP without autoloading of packages.

Hope this helps,

     Stefan Kohl

---------------------------------------------------------------------------
Stefan Kohl
Institut für Geometrie und Topologie
Pfaffenwaldring 57
Universität Stuttgart
70550 Stuttgart / Germany

E-mail: kohl at mathematik.uni-stuttgart.de
Web:    http://www.cip.mathematik.uni-stuttgart.de/~kohlsn/
---------------------------------------------------------------------------