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Related papers: Classification of outer actions of Z^N on O_2

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In this paper, we study $Z_2$ actions on a cell complex X having the cohomology ring isomorphic to that of the wedge sum $P^2 (n) V S^{3n}$ or $S^n V S^{2n} V S^{3n}$. We determine the possible fixed point sets depending on whether or not X…

Algebraic Topology · Mathematics 2010-09-28 Mahender Singh

This paper studies the rigidity properties of the abstract commensurator of the outer automorphism group of a universal Coxeter group of rank $n$, which is the free product $W_n$ of $n$ copies of $\mathbb{Z}/2\mathbb{Z}$. We prove that for…

Group Theory · Mathematics 2021-01-19 Yassine Guerch

We introduce a new class of actions of the group $\G$ on finite von Neumann algebras and call them twisted Bernoulli shift actions. We classify these actions up to conjugacy and give an explicit description of their centralizers. We also…

Operator Algebras · Mathematics 2014-08-07 Hiroki Sako

Following recent advances in the local theory of current-algebraic orbifolds we present the basic dynamics - including the {\it twisted KZ equations} - of each twisted sector of all outer-automorphic WZW orbifolds on so(2n). Physics-…

High Energy Physics - Theory · Physics 2010-01-07 O. Ganor , M. B. Halpern , C. Helfgott , N. A. Obers

We show that, up to strong cocycle conjugacy, every countable exact group admits a unique equivariantly $\mathcal{O}_2$-absorbing, pointwise outer action on the Cuntz algebra $\mathcal{O}_2$ with the quasi-central approximation property…

Operator Algebras · Mathematics 2021-06-23 Yuhei Suzuki

An action of a compact, in particular finite group on a C*-algebra is called properly outer if no automorphism of the group that is distinct from identity is implemented by a unitary element of the algebra of local multipliers of the…

Operator Algebras · Mathematics 2024-12-03 Costel Peligrad

We characterize the simplicity of Pimsner algebras for non-proper C*-correspondences. With the aid of this criterion, we give a systematic strategy to produce outer actions of unitary tensor categories on Kirchberg algebras. In particular,…

Operator Algebras · Mathematics 2025-09-15 Kan Kitamura

Let S be a connected orientable surface with finitely many punctures, finitely many boundary components, and genus at least 6. Then any C^1 action of the mapping class group of S on the circle is trivial. The techniques used in the proof of…

Dynamical Systems · Mathematics 2016-01-20 Kamlesh Parwani

We classify, up to orbit equivalence, the cohomogeneity one actions on the noncompact duals of the symmetric spaces G_2, SU_3 and the real oriented two-plane Grassmannians.

Differential Geometry · Mathematics 2013-12-12 Jurgen Berndt , Miguel Dominguez-Vazquez

We prove that if G is an abelian group of odd order then there is an isomorphism from the second quandle homology of the Takasaki quandle of G to the exterior square of G. In particular, for G=Z_k^n, k odd, we obtain Z_k^{n(n-1)/2}.…

Geometric Topology · Mathematics 2019-10-29 Maciej Niebrzydowski , Jozef H. Przytycki

We show that for any countable discrete maximally almost periodic group $G$ and any UHF algebra $A$, there exists a strongly outer product type action $\alpha$ of $G$ on $A$. We also show the existence of countable discrete almost abelian…

Operator Algebras · Mathematics 2014-09-02 Michael Y. Sun

We consider actions of Z^k, k \ge 2, by Anosov diffeomorphisms which are uniformly quasiconformal on each coarse Lyapunov distribution. These actions generalize Cartan actions for which coarse Lyapunov distributions are one-dimensional. We…

Dynamical Systems · Mathematics 2007-05-23 Boris Kalinin , Victoria Sadovskaya

We show an equivariant Kirchberg-Phillips-type absorption theorem for pointwise outer actions of discrete amenable groups on Kirchberg algebras with respect to natural model actions on the Cuntz algebras $\mathcal{O}_\infty$ and…

Operator Algebras · Mathematics 2018-10-04 Gabor Szabo

We prove that the group of outer automorphisms of the free Coxeter group $W_n$ is acylindrically hyperbolic in the sense of Osin. As an application, we observe that any CAT(0) space admitting a geometric action by Out($W_n$) must contain a…

Group Theory · Mathematics 2020-09-22 Brendan Burns Healy

We construct an example of a simple nuclear separable unital stably finite Z-stable C*-algebra along with an action of the circle such that the crossed product is simple but not Z-stable.

Operator Algebras · Mathematics 2023-12-22 Ilan Hirshberg

We calculate the Hochschild and cyclic cohomology of the $\mathbb Z_2$ toroidal orbifold $\mathcal A_\theta^{alg} \rtimes \mathbb Z_2$. We also calculate the Chern-Connes pairing of the even cyclic cohomology group with the known elements…

K-Theory and Homology · Mathematics 2019-11-22 Safdar Quddus

We prove that the spaces of $\Cinf$ orientation-preserving actions of $\Z^n$ on $[0,1]$ and nonfree actions of $\Z^2$ on the circle are connected.

Dynamical Systems · Mathematics 2019-02-20 Christian Bonatti , Hélène Eynard

Let $A$ and $B$ be simple separable nuclear monotracial C$^*$-algebras, and let $\alpha$ and $\beta$ be strongly outer actions of a countable discrete amenable group $\Gamma$ on $A$ and $B$, respectively. In this paper, we show that…

Operator Algebras · Mathematics 2023-07-13 Norio Nawata

We compute the Hochschild cohomology and homology of a class of quantum exterior algebras, with coefficients in twisted bimodules. As a result we obtain several interesting examples of the homological behavior of these algebras.

K-Theory and Homology · Mathematics 2007-08-30 Petter Andreas Bergh

We show that any faithful quasi-free actions of a finite group on the Cuntz algebra $\mathcal{O}_\infty$ are mutually conjugate, and that they are asymptotically representable.

Operator Algebras · Mathematics 2010-12-02 Pavle Goldstein , Masaki Izumi