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Related papers: Villadsen algebras are singly generated

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We show that the $C^*$-algebra of a countable directed graph is singly generated. As a consequence, any $C^*$-algebra generated by a countable family of projections and partial isometries satisfying Cuntz-Krieger relations is singly…

Operator Algebras · Mathematics 2026-01-06 Jakub Curda , Julian Gonzales , Victor Wu

We study $K$-stability for tensor products of diagonal AH-algebras with arbitrary C*-algebras. Our main result provides a characterization of $K$-stability: for a diagonal AH-algebra $A = \varinjlim (A_i, \varphi_i)$, $A \otimes B$ is…

Operator Algebras · Mathematics 2026-05-25 Apurva Seth

We construct a singly generated subalgebra of ${\mathcal K}({\mathcal H})$ which is non-amenable, yet is boundedly approximately contractible. The example embeds into a homogeneous von Neumann algebra. We also observe that there are singly…

Operator Algebras · Mathematics 2013-11-13 Yemon Choi

We construct Cartan subalgebras and hence groupoid models for classes of AH-algebras. Our results cover all AH-algebras whose building blocks have base spaces of dimension at most one as well as Villadsen algebras, and thus go beyond…

Operator Algebras · Mathematics 2023-07-11 Xin Li , Ali Imad Raad

It is shown that certain unital simple C*-algebras constructed by Villadsen are classified by the K0-group together with radius of comparison.

Operator Algebras · Mathematics 2023-04-12 George A. Elliott , Chun Guang Li , Zhuang Niu

Algebras generated by strictly positive matrices are described up to similarity, including the commutative, simple, and semisimple cases. We provide sufficient conditions for some block diagonal matrix algebras to be generated by a set of…

Combinatorics · Mathematics 2020-07-29 N. A. Kolegov

We show that every unital amenable separable simple $C^*$-algebra with finite tracial rank which satisfies the UCT has in fact tracial rank at most one. We also show that unital separable simple $C^*$-algebrass which are "tracially" locally…

Operator Algebras · Mathematics 2012-05-29 Huaxin Lin

Let $A$ be a $K$-subalgebra of the polynomial ring $S=K[x_1,\ldots,x_d]$ of dimension $d$, generated by finitely many monomials of degree $r$. Then the Gauss algebra $\GG(A)$ of $A$ is generated by monomials of degree $(r-1)d$ in $S$. We…

Algebraic Geometry · Mathematics 2018-11-09 Jürgen Herzog , Raheleh Jafari , Abbas Nasrollah Nejad

We construct a ``noncommutative'' Villadsen algebra $B$ and show that, given an extreme tracial state $\nu$ on its canonical AF subalgebra, the subset of $T(B)$ consisting of those tracial states that equal $\nu$ when restricted to the…

Operator Algebras · Mathematics 2026-04-23 George A. Elliott , Vincent M. Ruzicka

We introduce a class of recursive subhomogeneous algebras that we call diagonal subhomogeneous and we give a notion of diagonal maps between these algebras. We show that any simple limit of diagonal subhomogeneous algebras with diagonal…

Operator Algebras · Mathematics 2017-09-29 James Lutley

Let $A$ be a connected commutative $\C$-algebra with derivation $D$, $G$ a finite linear automorphism group of $A$ which preserves $D$, and $R=A^G$ the fixed point subalgebra of $A$ under the action of $G$. We show that if $A$ is generated…

Quantum Algebra · Mathematics 2013-12-18 Kenichiro Tanabe

In this paper, we associate an algebra A(T) to a triangulation T of a surface S with a set of boundary marking points. This algebra A(T) is gentle and Gorenstein of dimension one. We also prove that A(T) is cluster-tilted if and only if it…

Representation Theory · Mathematics 2009-07-01 Ibrahim Assem , Thomas Brüstle , Gabrielle Charbonneau-Jodoin , Pierre-Guy Plamondon

Let $V$ be a vertex algebra and $g$ an automorphism of $V$ of order $T$. We construct a sequence of associative algebras $\tilde{A}_{g,n}(V )$ for any $n\in(1/T)\mathbb{N}$, which are not depend on the conformal structure of $V$. We show…

Quantum Algebra · Mathematics 2025-06-03 Shun Xu

The generator problem was posed by Kadison in 1967, and it remains open until today. We provide a solution for the class of C*-algebras absorbing the Jiang-Su algebra Z tensorially. More precisely, we show that every unital, separable,…

Operator Algebras · Mathematics 2015-01-06 Hannes Thiel , Wilhelm Winter

A twisting system is one of the major tools to study graded algebras, however, it is often difficult to construct a (non-algebraic) twisting system if a graded algebra is given by generators and relations. In this paper, we show that a…

Rings and Algebras · Mathematics 2022-05-03 Masaki Matsuno

We show that every AF-algebra is generated by a single operator. This was previously unclear, since the invariant that assigns to a C*-algebra its minimal number of generators lacks natural permanence properties. In particular, it may…

Operator Algebras · Mathematics 2020-11-19 Hannes Thiel

In this paper, we study a class of simple OZ-type vertex operator algebras $V$ generated by simple Virasoro vectors $\omega^{ij}=\omega^{ji}$, $1\leq i<j\leq n$, $n\geq 3$. We prove that $V$ is uniquely determined by its Griess algebra…

Quantum Algebra · Mathematics 2025-10-13 Runkang Feng

It is conjectured by Ibrahim Assem, Ralf Schiffler and Vasilisa Shramchenko in "Cluster Automorphisms and Compatibility of Cluster Variables" that every cluster algebra is unistructural, that is to say, that the set of cluster variables…

Representation Theory · Mathematics 2016-02-22 Véronique Bazier-Matte

We define the notion of a twisted topological graph algebra associated to a topological graph and a $1$-cocycle on its edge set. We prove a stronger version of a Vasselli's result. We expand Katsura's results to study twisted topological…

Operator Algebras · Mathematics 2019-02-20 Hui Li

We compute the generator rank of a subhomgeneous C*-algebra in terms of the covering dimension of the pieces of its primitive ideal space corresponding to irreducible representations of a fixed dimension. We deduce that every Z-stable…

Operator Algebras · Mathematics 2022-06-14 Hannes Thiel
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