6 papers
Banach algebras associated to twisted étale groupoids: simplicity and pure infiniteness
Krzysztof Bardadyn, Bartosz KwaÅniewski, Andrew McKee
We define reduced and essential Banach algebras associated to a twisted étale (not necessarily Hausdorff) groupoid and extend some fundamental results…
Twisted operator algebras of self-similar groupoid actions on arbitrary graphs
B. K. KwaÅniewski, 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…
Fourier--Stieltjes category for twisted groupoid actions
Alcides Buss, Bartosz KwaÅniewski, 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…
Banach algebras associated to twisted étale groupoids: inverse semigroup disintegration and representations on -spaces
Krzysztof Bardadyn, Bartosz K. KwaÅniewski, Andrew McKee
We introduce Banach algebras associated to twisted étale groupoids and to twisted inverse semigroup actions. This provides a unifying framework for num…
Type semigroups for twisted groupoids and a dichotomy for groupoid C*-algebras
Bartosz K. KwaÅniewski, 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 relat…
Topologically free actions and ideals in twisted Banach algebra crossed products
K. Bardadyn, B. K. KwaÅniewski
We generalize the influential -algebraic result of Kawamura-Tomiyama and Archbold-Spielberg for crossed products of discrete transformation groups to the realm of Banach algeb…