Counting eigenvalues via the Krein signa
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Todd Kapitula; Panayotis G. Kevrekidis; Björn Sandstede
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Article
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2005
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Elsevier Science
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English
⚖ 60 KB
We improve [1: Theorem 3.2] by showing that the number of unstable eigenvalues plus the number of purely imaginary eigenvalues with negative Krein signature can be computed from the negative signature of the energy.