On the Approximation of Isolated Eigenvalues of Ordinary Differential Operators

On the basis property of the root function systems of regular boundary value problems for the Sturm-Liouville operator

On the Basis Property of the Root Functions of Differential Operators with Matrix Coefficients

On the Bethe-Sommerfeld conjecture for periodic Maxwell operators

On the boundary of the pseudospectrum and its fault points

On the Chebyshev properties of system of eigenfunctions for Sturm--Liouville problem with singular coefficients

On the comparison of the Dirichlet and Neumann counting functions

On the completeness of generalized eigenfunctions of elliptic cone operators

On the completeness of the system of root vectors for first-order systems

On the concentration-compactness phenomenon for the first Schrodinger eigenvalue

On the Construction of Isospectral Vectorial Sturm-Liouville Differential Equations

On the convergence of second order spectra and multiplicity

On the Differential Operators with Periodic Matrix Coefficients

On the Dirac and Pauli operators with several Aharonov-Bohm solenoids

On the Direct Cauchy Theorem in Widom Domains: Positive and Negative Examples

On the discrete spectrum of a family of differential operators

On the discrete spectrum of a spatial quantum waveguide with a disc window

On the discrete spectrum of complex banded matrices

On the discrete spectrum of non-selfadjoint operators

On the discrete spectrum of quantum layers