We prove for a large class of operators, , including block Jacobi matrices, if is a finite set, each point of which is an eigenvalue of finite multiplicity, then a finite coefficient stripped, , has . We use an abstract Dirichlet decoupling.
Cite this article
Barry Simon, On the Removal of Finite Discrete Spectrum by Coefficient Stripping. J. Spectr. Theory 1 (2011), no. 1, pp. 81–85DOI 10.4171/JST/3