I want to inform you that a bug in the function EquivalenceTest
has been found. This function tests whether two modules are
equivalent by testing whether the generators of the operating
matrix groups are simultaneously conjugate in the general linear
group. But if some of the generators of these matrix groups are
the identity matrix, then these generators are automatically deleted
from the list of generators of these matrix groups. This yields a
bug in EquivalenceTest which might return true in such cases even
if the modules are not equivalent.

Since this function is used in the computation of maximal submodules
and maximal subgroups of special ag groups, it is possible that these
functions do not return the complete list of maximal submodules /
maximal subgroups in the cases where EquivalenceTest returns
incorrect results.

The bug will be fixed in the next version of GAP. However,
if someone needs a fix to this bug urgently, we will provide a
running version of this function.

Best wishes, Bettina