Spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs

The adjacency operator of a graph has a spectrum and a class of scalar-valued spectral measures which have been systematically analyzed; it also has a spectral multiplicity function which has been less studied. The first purpose of this article is to review some examples of infinite graphs for which...

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Date:2024
Main Author: de la Harpe, Pierre
Format: Article
Language:English
Published: Lugansk National Taras Shevchenko University 2024
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Online Access:https://admjournal.luguniv.edu.ua/index.php/adm/article/view/2224
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Journal Title:Algebra and Discrete Mathematics

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Algebra and Discrete Mathematics
id oai:ojs.admjournal.luguniv.edu.ua:article-2224
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spelling oai:ojs.admjournal.luguniv.edu.ua:article-22242024-04-21T17:47:57Z Spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs de la Harpe, Pierre spectral graph theory, adjacency operator, spectral measure, spectral multiplicity function, unitarily equivalent operators, cospectral graphs, Jacobi matrix 05C50, 47A10 The adjacency operator of a graph has a spectrum and a class of scalar-valued spectral measures which have been systematically analyzed; it also has a spectral multiplicity function which has been less studied. The first purpose of this article is to review some examples of infinite graphs for which the spectral multiplicity function of the adjacency operator has been determined. The second purpose of this article is to show explicit examples of infinite connected graphs which are cospectral, i.e., which have unitarily equivalent adjacency operators, and also explicit examples of infinite connected graphs which are uniquely determined by their spectrum. Lugansk National Taras Shevchenko University The author acknowledges support of the Swiss NSF grant 200020-20040. 2024-04-21 Article Article Peer-reviewed Article application/pdf https://admjournal.luguniv.edu.ua/index.php/adm/article/view/2224 10.12958/adm2224 Algebra and Discrete Mathematics; Vol 37, No 1 (2024) 2415-721X 1726-3255 en https://admjournal.luguniv.edu.ua/index.php/adm/article/view/2224/pdf Copyright (c) 2024 Algebra and Discrete Mathematics
institution Algebra and Discrete Mathematics
collection OJS
language English
topic spectral graph theory
adjacency operator
spectral measure
spectral multiplicity function
unitarily equivalent operators
cospectral graphs
Jacobi matrix
05C50
47A10
spellingShingle spectral graph theory
adjacency operator
spectral measure
spectral multiplicity function
unitarily equivalent operators
cospectral graphs
Jacobi matrix
05C50
47A10
de la Harpe, Pierre
Spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs
topic_facet spectral graph theory
adjacency operator
spectral measure
spectral multiplicity function
unitarily equivalent operators
cospectral graphs
Jacobi matrix
05C50
47A10
format Article
author de la Harpe, Pierre
author_facet de la Harpe, Pierre
author_sort de la Harpe, Pierre
title Spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs
title_short Spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs
title_full Spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs
title_fullStr Spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs
title_full_unstemmed Spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs
title_sort spectral multiplicity functions of adjacency operators of graphs and cospectral infinite graphs
description The adjacency operator of a graph has a spectrum and a class of scalar-valued spectral measures which have been systematically analyzed; it also has a spectral multiplicity function which has been less studied. The first purpose of this article is to review some examples of infinite graphs for which the spectral multiplicity function of the adjacency operator has been determined. The second purpose of this article is to show explicit examples of infinite connected graphs which are cospectral, i.e., which have unitarily equivalent adjacency operators, and also explicit examples of infinite connected graphs which are uniquely determined by their spectrum.
publisher Lugansk National Taras Shevchenko University
publishDate 2024
url https://admjournal.luguniv.edu.ua/index.php/adm/article/view/2224
work_keys_str_mv AT delaharpepierre spectralmultiplicityfunctionsofadjacencyoperatorsofgraphsandcospectralinfinitegraphs
first_indexed 2024-04-21T19:20:17Z
last_indexed 2024-04-21T19:20:17Z
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