The speaker is Petr Siegl of the Mathematical Institute, University of Bern, Switzerland.
Abstract
We consider the spectral problem for the operator function associated to the damped wave equation. The basic qualitative properties of the spectrum are proved, namely the discreteness of complex eigenvalues and the localization of the essential spectrum. Various limits of the sequence of operator functions with dampings are analyzed next. The main tool is the approximation theory in eigenvalue problems for holomorphic Fredholm operator functions. The results are illustrated by examples, where the complex eigenvalues lie on the two half-lines forming an angle depending on n.
The talk is based on the results obtained with P. Freitas (GFM University of Lisbon, Portugal).
