Spectral spread of Graphs

碩士 === 國立交通大學 === 應用數學系所 === 100 === Abstract Given an n×n matrixM, the spread, φ(M), is essentially the diameter of its spectrum: φ(M) := max i;j |ρi − ρj |, where the maximal is taken over all pairs of eigenvalues (or nonzero eigenvalues in some cases) of M. We consider adjacent matrices, Laplacia...

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Bibliographic Details
Main Authors: Shih, Jeng-cheng, 施政成
Other Authors: Weng, Chih-wen
Format: Others
Language:zh-TW
Published: 2011
Online Access:http://ndltd.ncl.edu.tw/handle/07455290033859070793
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Summary:碩士 === 國立交通大學 === 應用數學系所 === 100 === Abstract Given an n×n matrixM, the spread, φ(M), is essentially the diameter of its spectrum: φ(M) := max i;j |ρi − ρj |, where the maximal is taken over all pairs of eigenvalues (or nonzero eigenvalues in some cases) of M. We consider adjacent matrices, Laplacian and signless Laplacian matrices which are commonly used in graph theory. After discussing relatedness on the graphs and their corresponding spreads, we discover the boundary which affects the spread, and use this result to find the graphs that may have the maximal or minimal spread.