Perturbation by differences of unbounded potentials (Q1825996)

Perturbation by unbounded potentials and corresponding eigenvalues are studied in the general framework of harmonic spaces. The results are applied to the Schrödinger equation \((\Delta -\mu)u=0\) on domains U in \({\mathbb{R}}^ n\), where \(\mu\) is a signed measure on \({\mathbb{R}}^ n\) such that \(\mu\) does not charge polar sets and \(\mu^-\) generates a finite potential.