A classical approach to eigenvalue problems associated with a pair of mixed regular Sturm-Liouville equations. I.
A completeness theorem relative to one-dimensional Schrödinger equations with energy-dependent potentials
A computational investigation of an integro-differential inequality with periodic potential.
A duality between Schrödinger operators on graphs and certain Jacobi matrices
A formal series solution of the one-dimensional Schrödinger equation
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 generalization of Gordon's theorem and applications to quasiperiodic Schrödinger operators.
A global factorization theorem for the ZS-AKNS system.
A KAM-theorem for some nonlinear partial differential equations
A Limit-Point Criterion for Separated Dirac Operators and a Little Known Result on Riccati's Equation.
A new approach to inverse spectral theory. I: Fundamental formalism.
A new approach to inverse spectral theory. II: General real potentials and the connection to the spectral measure.
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 new phase space localization technique with application to the sum of negative eigenvalues of Schrödinger operators
A nonlinear bounday value problem for a nonlinear ordinary differential operator in weighted Sobolev spaces.
A nonlinear scattering problem
A note on a linear spectral theorem for a class of first order systems in .
A Note on Eigenvalue Problems with Eigenvalue Parameter in the Boundary Conditions.
A note on eigenvalues of ordinary differential operators.
In this follow-up on the work of Fefferman-Seco [FS] an improved condition for the discrete eigenvalues of the operator -d2 / dx2 + V(x) is established for V(x) satisfying certain hypotheses. The eigenvalue condition in [FS] establishes eigenvalues of this operator to within a small error. Through an obervation due to C. Fefferman, the order of accuracy can be improved if a certain condition is true. This paper improves on the result obtained in [FS] by showing that this condition does indeed hold....