An Interlacing Property of the Signless Laplacian of Threshold Graphs

We show that for threshold graphs, the eigenvalues of the signless Laplacian matrix interlace with the degrees of the vertices. As an application, we show that the signless Brouwer conjecture holds for threshold graphs, i.e., for threshold graphs the sum of the $k$ largest eigenvalues is bounded by...

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Bibliographic Details
Published inThe Electronic journal of combinatorics Vol. 32; no. 1
Main Authors Helmberg, Christoph, Porto, Guilherme, Torres, Guilherme, Trevisan, Vilmar
Format Journal Article
LanguageEnglish
Published 28.02.2025
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ISSN1077-8926
1077-8926
DOI10.37236/12332

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Summary:We show that for threshold graphs, the eigenvalues of the signless Laplacian matrix interlace with the degrees of the vertices. As an application, we show that the signless Brouwer conjecture holds for threshold graphs, i.e., for threshold graphs the sum of the $k$ largest eigenvalues is bounded by the number of edges plus $k + 1$ choose $2$.
ISSN:1077-8926
1077-8926
DOI:10.37236/12332