Integral Cayley Multigraphs over Abelian and Hamiltonian Groups
Keyword(s):
It is shown that a Cayley multigraph over a group $G$ with generating multiset $S$ is integral (i.e., all of its eigenvalues are integers) if $S$ lies in the integral cone over the boolean algebra generated by the normal subgroups of $G$. The converse holds in the case when $G$ is abelian. This in particular gives an alternative, character theoretic proof of a theorem of Bridges and Mena (1982). We extend this result to provide a necessary and sufficient condition for a Cayley multigraph over a Hamiltonian group to be integral, in terms of character sums and the structure of the generating set.
2019 ◽
Vol 18
(04)
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pp. 1950077
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2000 ◽
Vol 61
(1)
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pp. 27-32
2019 ◽
Vol 13
(07)
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pp. 2050136
2006 ◽
Vol 17
(02)
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pp. 231-251
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2014 ◽
Vol 07
(04)
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pp. 1450062
2018 ◽
Vol 7
(4.10)
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pp. 1015
2016 ◽
Vol 24
(2)
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pp. 5-14
2017 ◽
Vol E100.A
(12)
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pp. 2764-2775
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