## Abstract The problem of the perturbation of an operator having a continuous spectrum and an isolated eigenvalue Ξ»~0~ is considered by means of the theory on embedded eigenvalues. The perturbation is divided up into two parts. One part is used for embedding the isolated eigenvalue Ξ»~0~. This embe
On Unstable Isolated and Embedded Eigenvalues
β Scribed by M. Demuth
- Publisher
- John Wiley and Sons
- Year
- 1977
- Tongue
- English
- Weight
- 362 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0025-584X
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β¦ Synopsis
Abstract
In this paper we consider the convergence behaviour of spectral concentration intervals for unstable eigenvalues. A criterion is given to decide after the perturbation whether the unstable eigenvalue was isolated or embedded in the unperturbed case.
π SIMILAR VOLUMES
A graph is called of type k if it is connected, regular, and has k distinct eigenvalues. For example graphs of type 2 are the complete graphs, while those of type 3 are the strongly regular graphs. We prove that for any positive integer n, every graph can be embedded in n cospectral, non-isomorphic
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