RemoveIndecomposable(d, mu)
The function RemoveIndecomposable removes the column from d which
corresponds to P(mu). This is sometimes useful when trying to
calculate a new decomposition matrix using Specht and want to test a
possible candidate for a yet to be identified PIM.
See also DecompositionMatrix DecompositionMatrix and
CrystalDecompositionMatrix CrystalDecompositionMatrix. This
function requires the package ``specht'' (see RequirePackage).
GAP 3.4.4