We give a comprehensive treatment of Sturm–Liouville operators whose coefficients are measures including a full discussion of self-adjoint extensions and boundary conditions, resolvents, and Weyl–Titchmarsh–Kodaira theory. We avoid previous technical restrictions and, at the same time, extend all results to a larger class of operators. Our operators include classical Sturm– Liouville operators,...

An inverse nodal problem consists in reconstructing this operator from the given zeros of their eigenfunctions. In this work, we are concerned with the inverse nodal problem of the Sturm-Liouville operator with eigenparameter dependent boundary conditions on a finite interval. We prove uniqueness theorems: a dense subset of nodal points uniquely determine the parameters of the boundary conditio...

Finite dynamic element methods are interpreted as Rayleigh-Ritz methods where the trial functions depend linearly on the eigenparameter. The positive eigenvalues of the corresponding cubic matrix eigenvalue problem are proved to be upper bounds of eigenvalues of the original problem which are usually better than the bounds that one gets from the corresponding nite element method.