Hannes Thiel

activity

20242026

collaborators

7 papers

math.OA2026

Ranks of operators and pureness of C*-algebras

Hannes Thiel

For simple, nonelementary C*-algebras, we show uniform density of functions realized as ranks of operators. It follows that strict comparison by traces forces almost divisibility,…

math.OA2025

Centrally pure C*-algebras

Francesc Perera, Hannes Thiel, Eduard Vilalta

We show that a separable C*-algebra $A$ is $Z$ -stable if and only if its uncorrected central sequence algebra $A^{'} \cap A_{U}$ is pure, if and only if Kirchberg'…

math.OA2025

The Global Glimm Property for C*-algebras of topological dimension zero

Ping Wong Ng, Hannes Thiel, Eduard Vilalta

We show that a C*-algebra with topological dimension zero has the Global Glimm Property (every hereditary subalgebra contains an almost full nilpotent element) if and only if it is…

math.OA2025

Extensions of pure C*-algebras

Francesc Perera, Hannes Thiel, Eduard Vilalta

Given a closed ideal $I$ in a C*-algebra $A$ , we show that $A$ is pure if and only if $I$ and $A / I$ are pure. More generally, we study permanence of comparison and divisibility pro…

math.OA2025

Strict comparison for twisted group C*-algebras

Sven Raum, Hannes Thiel, Eduard Vilalta

We prove that any reduced twisted group C*-algebra of a selfless group with the rapid decay property is selfless. As an application, we show that twisted group C*-algebras of acyli…

math.FA2024

Criteria for the existence of Schwartz Gabor frames over rational lattices

Ulrik Enstad, Hannes Thiel, Eduard Vilalta

We give an explicit criterion for a rational lattice in the time-frequency plane to admit a Gabor frame with window in the Schwartz class. The criterion is an inequality formulated…

math.OA2024

Pure C*-algebras

Ramon Antoine, Francesc Perera, Hannes Thiel +1

We demonstrate that pure C*-algebras form a robust class by proving that pureness follows from very weak comparison and divisibility properties. Using this, we show that every simp…