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On the number of simple eigenvalues of a graph

Published online by Cambridge University Press:  14 November 2011

Peter Rowlinson
Peter Rowlinson
Affiliation:
Department of Mathematics, University of Stirling, Stirling, Scotland
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Synopsis

Let Γ be a graph with n points, and let G be the group of automorphisms of Γ. An orbit of G on which G acts as an elementary abelian 2-group is said to be exceptional. It is shown that the number of simple eigenvalues of Γ is at most (5n+4t)/9, where t is the number of points of Γ lying in exceptional orbits of G.

Type
Research Article
Information
Proceedings of the Royal Society of Edinburgh Section A: Mathematics , Volume 94 , Issue 3-4 , 1983 , pp. 247 - 250
Copyright
Copyright © Royal Society of Edinburgh 1983

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