On the Kato-Rellich theorem and applications for multi-subordinate perturbations

In this paper, we study the so called Kato-Rellich theorem. We prove a similar result for multi-subordinate perturbation. Moreover, we apply this result to study a perturbed operator of Nagy and \(n \times n\) block matrices of linear operators. The obtained results are of importance to be applicated to study the Schrödinger operators. Finally, we give an application to a Gribov operator in Bargmann space.