Jon Aaronson
Title: IP-rigidity and eigenvalue groups

Abstract: We examine the class of increasing sequences of natural numbers which are IP-rigidity sequences for some weakly mixing probability preserving transformations. This property is related to certain subgroups of the circle including eigenvalue groups of dyadic towers over the adding machine. There will be examples, including a super-lacunary sequence which is not IP-rigid. Joint work with Maryam Hosseini & Mariusz Lemanczyk