6 papers · 1 filter
Topological full groups, invertible isometries, and automorphisms of groupoid algebras
Eusebio Gardella, Mathias Palmstrøm, Hannes Thiel
We show that the topological full group of a Hausdorff ample groupoid with compact unit space coincides with the group of homotopy classes of invertible isometries in pseudofunctio…
Asymptotic lifting for completely positive maps
Marzieh Forough, Eusebio Gardella, Klaus Thomsen
Let and be -algebras with separable, let be an ideal in , and let be a completely positive contractive linear map. We show that there is…
Prime and semiprime Lie ideals in C*-algebras
Eusebio Gardella, Kan Kitamura, Hannes Thiel
Using the theory of Dixmier ideals developed in previous work, we show that every semiprime Lie ideal in a C*-algebra arises as the full normalizer subspace of a semiprime two-side…
Rigidity of pseudofunction algebras of ample groupoids
Eusebio Gardella, Mathias Palmstrøm, Hannes Thiel
We show that a Hausdorff, ample groupoid can be completely recovered from the -norm completion of . More generally, we show that this is also the…
Simplicity of -algebras of contracting self-similar groups
Eusebio Gardella, Volodymyr Nekrashevych, Benjamin Steinberg +1
We show that the -algebra associated by Nekrashevych to a contracting self-similar group is simple if and only if the corresponding complex -algebra is simple. We also i…
Semiprime ideals in C*-algebras
Eusebio Gardella, Kan Kitamura, Hannes Thiel
We show that a not necessarily closed ideal in a C*-algebra is semiprime if and only if it is idempotent, if and only if it is closed under square roots of positive elements. Among…