16 citations · 40 across the 9 of their papers we have counts for
11 papers
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…
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…
Banach algebras associated to twisted étale groupoids: simplicity and pure infiniteness
Krzysztof Bardadyn, Bartosz Kwaśniewski, Andrew McKee
We define reduced and essential Banach algebras associated to a twisted étale (not necessarily Hausdorff) groupoid and extend some fundamental results f…
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…
Topologically free actions and ideals in twisted Banach algebra crossed products
K. Bardadyn, B. K. Kwaśniewski
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…
Banach algebras associated to twisted étale groupoids: inverse semigroup disintegration and representations on -spaces
Krzysztof Bardadyn, Bartosz K. Kwaśniewski, Andrew McKee
We introduce Banach algebras associated to twisted étale groupoids and to twisted inverse semigroup actions. This provides a unifying framework for nume…
Aperiodicity: the almost extension property and uniqueness of pseudo-expectations
Bartosz Kosma Kwaśniewski, Ralf Meyer
We prove implications among the conditions in the title for an inclusion of a C*-algebra A in a C*-algebra B, and we also relate this to several other properties in case B is a cro…
The Haagerup property for twisted groupoid dynamical systems
Bartosz Kwaśniewski, Kang Li, Adam Skalski
We introduce the Haagerup property for twisted groupoid -dynamical systems in terms of naturally defined positive-definite operator-valued multipliers. By developing a version…
Nica-Toeplitz algebras associated with right tensor -precategories over right LCM semigroups
Bartosz K. Kwaśniewski, Nadia S. Larsen
We introduce and analyze the full and the reduced Nica-Toeplitz algebra associated to an ideal…
Aperiodicity, topological freeness and pure outerness: from group actions to Fell bundles
Bartosz K. Kwaśniewski, Ralf Meyer
We generalise various non-triviality conditions for group actions to Fell bundles over discrete groups and prove several implications between them. We also study sufficient criteri…
On transfer operators for C*-dynamical systems
B. K. Kwaśniewski
The theme of the paper is the question of existence and basic structure of transfer operators for endomorphisms of a unital C*-algebra. We establish a complete description of non-d…