symmetric Schrödinger operators: reality of the perturbed eigenvalues.
Perron-Frobenius and Krein-Rutman theorems for tangentially positive operators
We study several aspects of a generalized Perron-Frobenius and Krein-Rutman theorems concerning spectral properties of a (possibly unbounded) linear operator on a cone in a Banach space. The operator is subject to the so-called tangency or weak range assumptions implying the resolvent invariance of the cone. The further assumptions rely on relations between the spectral and essential spectral bounds of the operator. In general we do not assume that the cone induces the Banach lattice structure into...
Planarizable supersymmetric quantum toboggans.
Properties of eigenfunctions of non-local operators