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Related papers: Viewing AF-algebras as graph algebras

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Finiteness conditions for $C^*$-algebras like AF-embeddability, quasidiagonality, stable finiteness have been studied by many authors and shown to be equivalent for certain classes of $C^*$-algebras. For example, Schfhauser proves that…

Operator Algebras · Mathematics 2020-08-26 Ja A Jeong , Gi Hyun Park

The algebra of basic covers of a graph G, denoted by \A(G), was introduced by Juergen Herzog as a suitable quotient of the vertex cover algebra. In this paper we show that if the graph is bipartite then \A(G) is a homogeneous algebra with…

Commutative Algebra · Mathematics 2015-03-17 Alexandru Constantinescu , Matteo Varbaro

We introduce a class of algebras over a field $\mathbb{F}$ related to directed graphs in which all edges are labeled by nonzero elements of the field $\mathbb{F}$. If all labels are different from $1$, these algebras are axial algebras. We…

Commutative Algebra · Mathematics 2026-03-05 Hans Cuypers

We will show that separable unital AF-algebras whose Bratteli diagrams do not allow converging two nodes into one node, can be classified up to the tensor product with the universal UHF-algebra $\Q$ only by their trace spaces. That is, if…

Operator Algebras · Mathematics 2020-09-11 Saeed Ghasemi

We review the notion of submanifold algebra, as introduced by T. Masson, and discuss some properties and examples. A submanifold algebra of an associative algebra $A$ is a quotient algebra $B$ such that all derivations of $B$ can be lifted…

Quantum Algebra · Mathematics 2020-06-11 Francesco D'Andrea

Given a positive definite even lattice and a commutative ring, there is a standard construction of a lattice vertex algebra over the commutative ring, and it admits a natural grading by non-negative integers. We describe the groups of…

Quantum Algebra · Mathematics 2026-02-18 Scott Carnahan , Hayate Kobayashi

The algebras for all possible Lorentzian and Euclidean kinematics with $\frak{so}(3)$ isotropy except static ones are re-classified. The geometries for algebras are presented by contraction approach. The relations among the geometries are…

Mathematical Physics · Physics 2013-01-25 Chao-Guang Huang , Yu Tian , Xiao-Ning Wu , Zhan Xu , Bin Zhou

We give a procedure to compute the rational homotopy groups of the group of quasi-unitaries of an AF-algebra. As an application, we show that an AF-algebra is K-stable if and only if it is rationally K-stable.

Operator Algebras · Mathematics 2020-11-03 Apurva Seth , Prahlad Vaidyanathan

Associated to any uniform finite layered graph Gamma there is a noncommutative graded quadratic algebra A(Gamma) given by a construction due to Gelfand, Retakh, Serconek and Wilson. It is natural to ask when these algebras are Koszul.…

Rings and Algebras · Mathematics 2010-11-08 Thomas Cassidy , Christopher Phan , Brad Shelton

We give various necessary and sufficient conditions for an AF-algebra to be isomorphic to a graph C*-algebra, an Exel-Laca algebra, and an ultragraph C*-algebra. We also explore consequences of these results. In particular, we show that all…

Operator Algebras · Mathematics 2009-05-24 Takeshi Katsura , Aidan Sims , Mark Tomforde

Building on recent work of Robertson and Steger, we associate a C*-algebra to a combinatorial object which may be thought of as a higher rank graph. This C*-algebra is shown to be isomorphic to that of the associated path groupoid.…

Operator Algebras · Mathematics 2007-05-23 Alex Kumjian , David Pask

We prove that every AF-algebra is isomorphic to a crossed product of a commutative AF-algebra by a partial automorphism. The case of UHF-algebras is treated in detail.

funct-an · Mathematics 2008-02-03 Ruy Exel

In this paper we generalise an application of Matui's HK conjecture by Farsi, Kumjian, Pask, and Sims, that gives an isomorphism from the homology groups of AF groupoids to the corresponding K-theory. We give an explicit formula for this…

Operator Algebras · Mathematics 2025-05-08 Rafael P. Lima

We introduce a tropical version of the Fukaya algebra of a Lagrangian submanifold. Tropical graphs arise as large-scale behavior of pseudoholomorphic disks under a multiple cut operation on a symplectic manifold that produces a collection…

Symplectic Geometry · Mathematics 2025-08-28 Sushmita Venugopalan , Chris Woodward

We functorially characterize groupoids as special dagger Frobenius algebras in the category of sets and relations. This is then generalized to a non-unital setting, by establishing an adjunction between H*-algebras in the category of sets…

Category Theory · Mathematics 2012-12-05 Chris Heunen , Ivan Contreras , Alberto S. Cattaneo

We construct a functor which maps conjugate pseudo-Anosov automorphisms of a surface to the so-called stably isomorphic stationary AF-algebras; the functor gives new topological invariants of three dimensional manifolds coming from the…

Geometric Topology · Mathematics 2013-08-09 Igor Nikolaev

We consider Fell bundles over discrete groups, and the C*-algebra which is universal for representations of the bundle. We define deformations of Fell bundles, which are new Fell bundles with the same underlying Banach bundle but with the…

Operator Algebras · Mathematics 2016-06-01 Iain Raeburn

We study certain $q$-deformed analogues of the maximal abelian subalgebras of the group von Neumann algebras of free groups. The radial subalgebra is defined for Hecke deformed von Neumann algebras of the Coxeter group…

Operator Algebras · Mathematics 2019-11-27 Martijn Caspers , Adam Skalski , Mateusz Wasilewski

Consider a compact locally symmetric space $M$ of rank $r$, with fundamental group $\Gamma$. The von Neumann algebra $\vn(\Gamma)$ is the convolution algebra of functions $f\in\ell_2(\Gamma)$ which act by left convolution on…

Operator Algebras · Mathematics 2013-02-25 Guyan Robertson

The subalgebra of diagonal elements of a quantum matrix group has been conjectured by Daniel Krob and Jean-Yves Thibon to be isomorphic to a cubic algebra, coined the quantum pseudo-plactic algebra. We present a functorial approach to the…

Quantum Algebra · Mathematics 2019-12-10 Todor Popov