Determining whether or not a given finitely generated group is
permutation stable is in general a difficult problem. In this talk
we discuss work of Becker, Lubotzky and Thom which gives, in the
case of amenable groups, a necessary and sufficient...
The aim of this talk is to show that C*-algebras are useful for
studying stability of groups. In particular we will discuss some
obstructions for Hilbert-Schmidt stability of groups, obtain a
complete characterization of Hilbert-Schmidt stability...
In his seminal paper from 1973, Garland introduced a machinery
for proving vanishing of group cohomology for groups acting on
Bruhat-Tits buildings. This machinery, known today as
“Garland’s method”, had several applications as a
tool for proving...
Several well-known open questions (such as: are all groups
sofic/hyperlinear?) have a common form: can all groups be
approximated by asymptotic homomorphisms into the symmetric
groups Sym(n)Sym(n) (in the sofic case) or the finite
Let C be a class of groups. (For example, C is a class of all
finite groups, or C is a class of all finite symmetric groups.) I
give a definition of approximations of a group G by groups from C.
For example, the groups approximable by symmetric...
In this talk I will present a joint work with Arie Levit and
Yair Minsky on flexible stability of surface groups. The proof will
be geometric in nature and will rely on an analysis of branched
covers of hyperbolic surfaces. Along the way we will see...