∣ . (1) As already concluded by Bardeen and Wagoner, the general expectation is that this also holds for other spacetimes containing a central rigidly rotating perfect fluid. The recent work of Bradley and Fodor [2] lends support for this in the slowly rotating case. It is now interesting to ask the question whether this holds not only for the quadrupole moment but for every moment, |Qn| ≥ |Qn,...