Relatively Bounded Perturbations of J-Non-Negative Operators

Abstract We improve known perturbation results for self-adjoint operators in Hilbert spaces and prove spectral enclosures diagonally dominant J -self-adjoint operator matrices. These are used the proof of central result, a theorem -non-negative operators. The applied to singular indefinite Sturm-Liouville with $$L^p$$ L p -potentials. Known bounds on non-real eigenvalues such improved.