Graphs with many valencies and few eigenvalues

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Graphs with many valencies and few eigenvalues

Dom de Caen posed the question whether connected graphs with three distinct eigenvalues have at most three distinct valencies. We do not answer this question, but instead construct connected graphs with four and five distinct eigenvalues and arbitrarily many distinct valencies. The graphs with four distinct eigenvalues come from regular two-graphs. As a side result, we characterize the disconne...

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Graphs with few distinct distance eigenvalues irrespective of the diameters

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Nonsingular mixed graphs with few eigenvalues greater than two

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Small graphs with exactly two non-negative eigenvalues

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ژورنال

عنوان ژورنال: The Electronic Journal of Linear Algebra

سال: 2015

ISSN: 1081-3810

DOI: 10.13001/1081-3810.2987