61 citations · 80 across the 8 of their papers we have counts for
5 papers · 1 filter
Graph morphisms as groupoid actors
Gilles G. de Castro, Ralf Meyer
We describe proper actors from the underlying groupoid of a graph C*-algebra to another étale groupoid in terms of bisections. This allows to understand graph morphisms and the *-h…
The Baum-Connes conjecture for extensions
Ralf Meyer
This note provides a counterexample showing that the assumptions that Chabert and Echterhoff have imposed in their permanence property of the Baum-Connes conjecture for group exten…
Bicategories of C*-correspondences as Dwyer-Kan localisations
Ralf Meyer
We show that the bicategory of proper correspondences is the Dwyer-Kan localisation of the category of C*-algebras at a certain class of *-homomorphisms.
Groupoid models for relative Cuntz-Pimsner algebras of groupoid correspondences
Ralf Meyer
A groupoid correspondence on an etale, locally compact groupoid induces a C*-correspondence on its groupoid C*-algebra. We show that the Cuntz-Pimsner algebra for this C*-correspon…
Type semigroups for twisted groupoids and a dichotomy for groupoid C*-algebras
Bartosz K. Kwaśniewski, Ralf Meyer, Akshara Prasad
We develop a theory of type semigroups for arbitrary twisted, not necessarily Hausdorff étale groupoids. The type semigroup is a dynamical version of the Cuntz semigroup. We relate…