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Related papers: Semigroupoid C*-Algebras

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We show that semigroup C*-algebras are groupoid C*-algebras.

Operator Algebras · Mathematics 2019-06-14 Hui Li

We study groupoids and semigroup C*-algebras arising from graphs of monoids, in the setting of right LCM monoids. First, we establish a general criterion when a graph of monoids gives rise to a submonoid of the fundamental group which is…

Operator Algebras · Mathematics 2022-12-06 Cheng Chen , Xin Li

Certain $*$-semigroups are associated with the universal $C^*$-algebra generated by a partial isometry, which is itself the universal $C^*$-algebra of a $*$-semigroup. A fundamental role for a $*$-structure on a semigroup is emphasized, and…

Operator Algebras · Mathematics 2014-06-03 Berndt Brenken

We introduce $C^*$-algebras associated with directed graphs, along with two generalizations of this concept, namely Exel-Pardo $C^*$-algebras associated with a self-similar action of a group on a directed graph, and the $C^*$-algebras…

Operator Algebras · Mathematics 2026-04-21 Pere Ara

Let $\Lambda = \mathbb{Z}^n$ with lexicographic ordering. $\Lambda$ is a totally ordered group. Let $X = \Lambda^+ * \Lambda^+$. Then $X$ is a $\Lambda$-tree. Analogous to the construction of graph $C^*$-algebras, we form a groupoid whose…

Operator Algebras · Mathematics 2011-01-31 Menassie Ephrem

In this paper, we discuss a method of constructing separable representations of the $C^*$-algebras associated to strongly connected row-finite $k$-graphs $\Lambda$. We begin by giving an alternative characterization of the…

Operator Algebras · Mathematics 2018-03-26 Carla Farsi , Elizabeth Gillaspy , Palle E. T. Jorgensen , Sooran Kang , Judith Packer

We provide a framework for studying concrete C*-algebras associated with algebraic actions of semigroups: Given such an action, we construct an inverse semigroup, and we introduce conditions for algebraic actions that characterize…

Operator Algebras · Mathematics 2024-01-25 Chris Bruce , Xin Li

We define equivariant semiprojectivity for C*-algebras equipped with actions of compact groups. We prove that the following examples are equivariantly semiprojective: arbitrary finite dimensional C*-algebras with arbitrary actions of…

Operator Algebras · Mathematics 2011-12-21 N. Christopher Phillips

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 develop a theory of type semigroups for arbitrary twisted, not necessarily Hausdorff \'etale groupoids. The type semigroup is a dynamical version of the Cuntz semigroup. We relate it to traces, ideals, pure infiniteness, and stable…

Operator Algebras · Mathematics 2025-03-28 Bartosz K. Kwaśniewski , Ralf Meyer , Akshara Prasad

We define a semidirect product groupoid of a system of partially defined local homeomorphisms $T=(T_{1},..., T_{r})$. We prove that this construction gives rise to amenable groupoids. The associated algebra is a Cuntz-like algebra. We use…

Operator Algebras · Mathematics 2008-11-12 Ionel Popescu , Iulian Popescu

We provide inverse semigroup and groupoid models for the Toeplitz and Cuntz-Krieger algebras of finitely aligned higher-rank graphs. Using these models, we prove a uniqueness theorem for the Cuntz-Krieger algebra.

Operator Algebras · Mathematics 2007-05-23 Cynthia Farthing , Paul S. Muhly , Trent Yeend

We describe the $C^*$-algebra of an $E$-unitary or strongly 0-$E$-unitary inverse semigroup as the partial crossed product of a commutative $C^*$-algebra by the maximal group image of the inverse semigroup. We give a similar result for the…

Operator Algebras · Mathematics 2015-12-08 David Milan , Benjamin Steinberg

We study C*-algebras associated with subsemigroups of groups. For a large class of such semigroups including positive cones in quasi-lattice ordered groups and left Ore semigroups, we describe the corresponding semigroup C*-algebras as…

Operator Algebras · Mathematics 2012-05-14 Xin Li

Many interesting examples of operator algebras, both self-adjoint and non-self-adjoint, can be constructed from directed graphs. In this survey, we overview the construction of $C^*$-algebras from directed graphs and from two…

Operator Algebras · Mathematics 2022-09-07 Juliana Bukoski , Sushil Singla

This dissertation concerns the classification of groupoid and higher-rank graph C*-algebras and has two main components. Firstly, for a groupoid it is shown that the notions of strength of convergence in the orbit space and…

Operator Algebras · Mathematics 2013-05-28 Robert Hazlewood

In a recent paper, Pardo and the first named author introduced a class of C*-algebras which which are constructed from an action of a group on a graph. This class was shown to include many C*-algebras of interest, including all Kirchberg…

Operator Algebras · Mathematics 2014-06-30 Ruy Exel , Charles Starling

Graph inverse semigroups generalize the polycyclic inverse monoids and play an important role in the theory of C*-algebras. This paper has two main goals: first, to provide an abstract characterization of graph inverse semigroups; and…

Category Theory · Mathematics 2013-08-14 David G. Jones , Mark V. Lawson

We generalize the Li-Yang notion of self-similar $k$-graph $(G,\Lambda)$ and its $C^*$-algebra $\mathcal{O}_{G,\Lambda}$ to any finitely aligned $k$-graph $\Lambda$. We then introduce an inverse semigroup model for $\mathcal{O}_{G,\Lambda}$…

Operator Algebras · Mathematics 2024-11-22 Hossein Larki

We introduce the notion of continuous orbit equivalence for partial dynamical systems, and give an equivalent characterization in terms of Cartan-isomorphisms for partial C*-crossed products. Both graph C*-algebras and semigroup C*-algebras…

Operator Algebras · Mathematics 2016-03-31 Xin Li
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