Monday, January 11, 2021
12:00 PM -
1:00 PM
Online Event
Logic Seminar
Series: Logic Seminar Series
A new regularity property of the Haar null ideal
Zoltán Vidnyánszky,
Department of Mathematics,
Caltech,
Christensen's Haar null ideal is a well-behaved generalization of Haar null sets to groups, which admit no Haar measure. We show that in the group ZωZω, every Haar positive (that is, non-Haar null) analytic set contains a Haar positive closed set. Using this result, we determine the exact Wadge class of the family of Haar null closed subsets of ZωZω.
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