A completeness theorem relative to one-dimensional Schrödinger equations with energy-dependent potentials
A generalization of a theorem of Mammana
We prove that any linear ordinary differential operator with complex-valued coefficients continuous in an interval I can be factored into a product of first-order operators globally defined on I. This generalizes a theorem of Mammana for the case of real-valued coefficients.
A Limit-Point Criterion for Separated Dirac Operators and a Little Known Result on Riccati's Equation.
A new method for obtaining eigenvalues of variational inequalities. Branches of eigenvalues of the equation with the penalty in a special case
A new method for obtaining eigenvalues of variational inequalities based on bifurcation theory
A nonlinear scattering problem
A Note on Eigenvalue Problems with Eigenvalue Parameter in the Boundary Conditions.
A note on higher monotonicity properties of certain Sturm-Liouville functions. III
A note on higher monotonicity properties of certain Sturm-Liouville functions. II.
A Note on Pairs of Solutions of a Nonlinear Sturm-Liouville Problem.
A proof of monotony of the Temple quotients in eigenvalue problems
If the so-called Collatz method is applied to get twosided estimates of the first eigenvalue , the sequences of the so-called Schwarz quatients (which are upper bounds for ) and of the so-called Temple quotients (which are lower bounds) are constructed. While monotony of the first sequence was proved many years ago, monotony of the second one has been proved only recently by F. goerisch and J. Albrecht in their common paper “Die Monotonie der Templeschen Quotienten” (ZAMM, in print). In the present...
A remark to one result of M. E. Muldoon
A singular Sturm-Liouville problem treated by non-standard analysis.
Absolut stetiges Spektrum bei Sturm-Liouville-Operatoren und Dirac-Systemen.
Absolute Continuity of the Essential Spectrum of - ... + q (t) without Monotony of q.
Absolutely convergent expansions associated with a boundary-value problem with the eigenvalue parameter contained in one boundary condition
An a posteriori Error Estimation of the Rayleigh-Ritz Eigenvalues.
An example of a Schroedinger equation with almost periodic potential and nowhere dense spectrum.
An extension of a result by Dinaburg and Sinai on quasi-periodic potentials.
An upper estimation for the eigenfrequencies of vibrating Liapunoff bodies (first boundary value problem).