> ^ From:

^ Subject:

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

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