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New Radon–Nikodym ideals

  • Vladimir Kanovei (a1) and Michael Reeken (a2)


Farah recently proved that many Borel P-ideals. on satisfy the following requirement: any measurable homomorphism has a continuous lifting which is a homomorphism itself. Ideals having such a property were called Radon–Nikodym (RN) ideals. Answering some Farah's questions, it is proved that many non-P ideals, including, for instance, Fin ⊗ Fin, are Radon–Nikodym. To prove this result, another property of ideals called the Fubini property, is introduced, which implies RN and is stable under some important transformations of ideals.



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New Radon–Nikodym ideals

  • Vladimir Kanovei (a1) and Michael Reeken (a2)


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