The study of perturbed eigenvalue problems has been a very active field investigation throughout the years. In this survey we collect several results in field.

Abstract This paper addresses particular eigenvalue problems within the context of two quaternionic function theories. More precisely, we study concrete classes problems, first one for slice derivative operator in class slice-regular functions and second Cauchy–Riemann–Fueter axially monogenic functions. The are related to each other by four-dimensional Laplace Fueter’s Theorem. As an applicati...

The dynamic analysis of structures using the nite element method leads to very large eigenvalue problems. Condensation is often required to reduce the number of degrees of freedom of these problems to manageable size. The (statically or dynamically) condensed problem can be considered as linearization of a matrix eigenvalue problem which is nonlinear with respect to the eigenparameter. As a con...