Friday, January 17 at 3:30pm to 4:30pm
Kaprielian Hall (KAP), 414
3620 South Vermont Avenue, Los Angeles, CA 90089
Tianyi Zheng, UC San Diego
A group is called permutation stable if almost homomorphisms to the symmetric groups must be close to actual homomorphisms asymptotically. Recently Becker, Lubotzky and Thom showed a characterization of permutation stability for amenable groups in terms of invariant random subgroups (IRSs). We will discuss some examples of amenable groups acting on the rooted tree, including Grigorchuk groups, whose IRSs have special properties. The information on IRSs allows to verify the Becker-Lubotzky-Thom criterion, thus providing a large collection of permutation stable groups.