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5 votes
1 answer
250 views

Function algebra of Furstenberg boundary $\partial_F \Gamma$: when is it a $W^*$-algebra?

Let $\Gamma$ be a non-amenable discrete group and consider its Furstenberg boundary $\partial_F \Gamma$. It is known that this is a compact topological space which is stonean (equivalently: extremely ...
J. De Ro's user avatar
  • 525
3 votes
1 answer
285 views

Extreme points of the set of all traces

Let $G$ be a finitely generated group with a bound on its complex unitary irreducible representations: That is assume all complex unitary irreducibles of $G$ have degrees at most $k$ for some integer $...
user3826143's user avatar
9 votes
1 answer
372 views

Simplicity of group $C^\ast$-algebra implies fullness of group-von Neumann algebra?

Let $\Gamma$ be a discrete group whose reduced group $C^\ast$-algebra is simple. Can we conclude that the corresponding group-von Neumann algebra $\mathcal{L}(G)$ is a full $\text{II}_1$-factor, ...
worldreporter's user avatar
0 votes
1 answer
204 views

A certain class of representations

Let $g$ be a non-identity element in a torsion-free amenable group, does there exist a finite-dimensional unitary representation $\pi$ with $\pi(g)\neq 1$? (The word "finite-dimensional" was ...
MSMalekan's user avatar
  • 2,118
4 votes
1 answer
1k views

Murray–von Neumann equivalence on C$^*$-algebra and von Neumann algebra

Let $H$ be a separable infinite dimensional Hilbert space, $M \subset B(H)$ a von Neumann algebra and $A \subset M$ a separable $C^*$-algebra such that $A''=M$. Let $p,q \in M_{\infty}(A)$ be (...
Sebastien Palcoux's user avatar