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Dear Bill, dear Forum,

the soluble minimal normal subgroups of a group G can also be

computed using the function `AllInvariantSubgroupsWithNProperty' in

the GAP package CRISP. It should work very efficiently, even for very

large groups, and can easily be modified to just compute special

types of minimal normal subgroups. Please find a code example below.

All the best,

Burkhard Hoefling.

SolvableMinimalNormalSubgroups := function (G)

local norms, k;

norms := AllInvariantSubgroupsWithNProperty (G, FittingSubgroup (G),

function (U, V, R, data)

return IsTrivial(R);

end,

ReturnFail,

[]);

# remove trivial subgroup - in the current implementation, this is always # the last group in the list, but better check... k := Length (norms); while not IsTrivial (norms[k]) do k := k - 1; od; norms{[k..Length(norms)-1]} := norms{[k+1..Length(norms)]}; Unbind (norms[Length(norms)]); return norms; end;

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