3 papers
math.OA2025
A note on the quasi-local algebra of expander graphs
Bruno M. Braga, Ján Špakula, Alessandro Vignati
We show that the quasi-local algebra of a coarse disjoint union of expander graphs does not contain a Cartan subalgebra isomorphic to . N. Ozawa has recently shown tha…
math.GR2024
Boundary representations of hyperbolic groups: the log-Sobolev case
Kevin Boucher, Ján Špakula
We study boundary representations of hyperbolic groups on the (compactly embedded) function space , the domain of the logarithmic L…
math.OA2009
Non-K-exact uniform Roe C*-algebras
Jan Spakula
We prove that uniform Roe C*-algebras associated to some expander graphs coming from discrete groups with property (τ) are not K-exact. In particular, we show that this is the case…