English

On Krein-Milman theorem for the space of sofic representations

Functional Analysis 2021-07-06 v1

Abstract

Denote by Sof(G)Sof(G) the space of sofic representations of a countable group GG. This space is known by a result of the second author, to have a convex-like structure. We show that, in this space, minimal faces are extreme points. We then construct uncountable many extreme points for Sof(F2)Sof(\mathbb{F}_2) and show that there exists a decreasing chain of closed faces with empty intersection. Finally we construct a strangely looking sofic representation in Sof(F2)Sof(\mathbb{F}_2) that we believe it is outside of the closure of the convex hull of extreme points.

Keywords

Cite

@article{arxiv.2107.01236,
  title  = {On Krein-Milman theorem for the space of sofic representations},
  author = {Radu B. Munteanu and Liviu Paunescu},
  journal= {arXiv preprint arXiv:2107.01236},
  year   = {2021}
}

Comments

16 pages

R2 v1 2026-06-24T03:51:16.175Z