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We construct the crossed product of a C(X)-algebra by an endomorphism, in such a way that the endomorphism itself becomes induced by the bimodule of continuous sections of a vector bundle. Some motivating examples for such a construction…

Operator Algebras · Mathematics 2011-11-21 Ezio Vasselli

The unions of directed graphs are the simplest examples of pushouts of directed graphs. The conditions under which they contravariantly induce surjective gauge-equivariant pullbacks of graph C*-algebras have been well studied and vastly…

Rings and Algebras · Mathematics 2025-07-18 Piotr M. Hajac , Mariusz Tobolski

We consider the problem of identifying exactly which AF-algebras are isomorphic to a graph C*-algebra. We prove that any separable, unital, Type I C*-algebra with finitely many ideals is isomorphic to a graph C*-algebra. This result allows…

Operator Algebras · Mathematics 2013-08-26 Soren Eilers , Takeshi Katsura , Efren Ruiz , Mark Tomforde

We provide a complete classification of the class of unital graph $C^*$-algebras - prominently containing the full family of Cuntz-Krieger algebras - showing that Morita equivalence in this case is determined by ordered, filtered…

Operator Algebras · Mathematics 2021-09-20 Søren Eilers , Gunnar Restorff , Efren Ruiz , Adam P. W. Sørensen

We consider when automorphisms of a graph can be induced by homeomorphisms of embeddings of the graph in a $3$-manifold. In particular, we prove that every automorphism of a graph is induced by a homeomorphism of some embedding of the graph…

Geometric Topology · Mathematics 2021-12-15 Erica Flapan , Song Yu

We present an overview of the recent developments in the study of the classification problem for automorphisms of C*-algebras from the perspective of Borel complexity theory.

Logic · Mathematics 2015-01-14 Martino Lupini

In modern mathematics, graphs figure as one of the better-investigated class of mathematical objects. Various properties of graphs, as well as graph-processing algorithms, can be useful if graphs of a certain kind are used as denotations…

Logic in Computer Science · Computer Science 2007-05-23 Alex Shkotin

This paper introduces a new graph construction, the permutational power of a graph, whose adjacency matrix is obtained by the composition of a permutation matrix with the adjacency matrix of the graph. It is shown that this construction…

Combinatorics · Mathematics 2019-10-29 Matteo Cavaleri , Daniele D'Angeli , Alfredo Donno

We consider complete graphs with edge weights and/or node weights taking values in some set. In the first part of this paper, we show that a large number of graphs are completely determined, up to isomorphism, by the distribution of their…

Combinatorics · Mathematics 2007-10-11 Mireille Boutin , Gregor Kemper

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

Graphical causal models are an important tool for knowledge discovery because they can represent both the causal relations between variables and the multivariate probability distributions over the data. Once learned, causal graphs can be…

Artificial Intelligence · Computer Science 2017-04-11 Andrew J Sedgewick , Joseph D. Ramsey , Peter Spirtes , Clark Glymour , Panayiotis V. Benos

A graph $G$ with vertex set $V(G)$ and edge set $E(G)$ is said to be word-representable if there exists a word $w$ over the alphabet $V(G)$ such that, for any two distinct letters $x,y \in V(G)$, the letters $x$ and $y$ alternate in $w$ if…

Combinatorics · Mathematics 2026-04-14 Eshwar Srinivasan , Ramesh Hariharasubramanian

In this paper it is shown that it is possible to associate several polynomial ideals to a directed graph $D$ in order to find properties of it. In fact by using algebraic tools it is possible to give appropriate procedures for automatic…

Commutative Algebra · Mathematics 2007-05-23 Giuseppa Carrá Ferro , Daniela Ferrarello

We characterise when the Leavitt path algebras over $\mathbb{Z}$ of two arbitrary countable directed graphs are $*$-isomorphic by showing that two Leavitt path algebras over $\mathbb{Z}$ are $*$-isomorphic if and only if the corresponding…

Rings and Algebras · Mathematics 2018-04-12 Toke Meier Carlsen

The monography examines the problem of constructing a group of automorphisms of a graph. A graph automorphism is a mapping of a set of vertices onto itself that preserves adjacency. The set of such automorphisms forms a vertex group of a…

History and Overview · Mathematics 2024-07-18 Sergey Kurapov , Maxim Davidovsky

Let \alpha:G --> G be an endomorphism of a discrete amenable group such that [G:\alpha(G)]<infinity. We study the structure of the C^* algebra generated by the left convolution operators acting on the left regular representation space,…

Operator Algebras · Mathematics 2007-05-23 Ilan Hirshberg

Hierarchical graph clustering is a common technique to reveal the multi-scale structure of complex networks. We propose a novel metric for assessing the quality of a hierarchical clustering. This metric reflects the ability to reconstruct…

Social and Information Networks · Computer Science 2018-07-16 Thomas Bonald , Bertrand Charpentier

We initiate a detailed and systematic study of automorphisms of the Cuntz algebras $\O_n$ which preserve both the diagonal and the core $UHF$-subalgebra. A general criterion of invertibility of endomorphisms yielding such automorphisms is…

Operator Algebras · Mathematics 2011-10-21 Roberto Conti , Wojciech Szymanski

We define the categorical cohomology of a k-graph \Lambda\ and show that the first three terms in this cohomology are isomorphic to the corresponding terms in the cohomology defined in our previous paper. This leads to an alternative…

Operator Algebras · Mathematics 2013-08-15 Alex Kumjian , David Pask , Aidan Sims

In the paper Graphical complexity of products of permutation groups, M. Grech, A. Jez, A. Kisielewicz have proved that the direct product of automorphism groups of edge-colored graphs is itself the automorphism groups of an edge-colored…

Combinatorics · Mathematics 2019-03-19 Mariusz Grech