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math.OA2025
Twisted operator algebras of self-similar groupoid actions on arbitrary graphs
B. K. Kwaśniewski, A. Mundey
We study self-similar groupoid actions on arbitrary directed graphs together with -valued twists that exhaust the second cohomology group of the associated Zappa-Szép p…
math.OA2025
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…
math.OA2024
Fourier--Stieltjes category for twisted groupoid actions
Alcides Buss, Bartosz Kwaśniewski, Andrew McKee +1
We extend the theory of Fourier--Stieltjes algebras to the category of twisted actions by étale groupoids on arbitrary C*-bundles, generalizing theories constructed previously by B…