Let Q IFP be any quantiier such that FO(Q IFP), rst order logic enhanced with Q IFP and its vectorizations, equals inductive xed point logic, IFP in expressive power. It is known that for certain quantiiers Q, the equivalence FO(Q IFP) IFP is no longer true if Q is added on both sides 12, 13]. Rather, we have FO(Q IFP ; Q) < IFP(Q) in such cases. We extend these results to a great variety of qu...