Caltech Home > PMA Home > Master Calendar > Logic Seminar
open search form
Monday, January 11, 2021
12:00 PM - 1:00 PM
Online Event

Logic Seminar

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.

For more information, please contact Math Department by phone at 626-395-4335 or by email at mathinfo@caltech.edu.