On the essential approximate point spectrum II
On the essential order spectrum
On the essential spectra of matrix operators and applications.
On the Essential Spectrum of Schrödinger Operators with Spherically Symmetric Potentials.
On the existence and regularity of solutions of linear equations in spaces
On the Existence of Minimal Operators for Schrödinger-Type Differential Expressions.
On the existence of multiple principal eigenvalues for some indefinite linear eigenvalue problems.
We study the existence of principal eigenvalues for differential operators of second order which are not necessarily in divergence form. We obtain results concerning multiplicity of principal eigenvalues in both the variational and the general case. Our approach uses systematically the Krein-Rutman theorem and fixed point arguments for the inverse of the spectral radius of some associated problems. We also use a variational characterization for both the self-adjoint and the general case.
On the existence of solution of the equation and a generalized coincidence degree theory. II.
On the existence of solution of the equation and a generalized coincidence degree theory. I.
On the Existence of Wave Operators for Dirac Operators.
On the exponential of a bounded linear operator in a L(E,E) algebra
On the extension of linear operators.
On the Fast Convergence of a Galerkin-Like Method for Equations of the Second Kind.
On the fine spectra of some averaging operators.
On the fine spectrum of generalized upper double-band matrices over the sequence space
On the fine spectrum of the generalized difference operator over the sequence spaces and .
On the Fine Structure of Spectra.
On the finite dimensional orbits of linear operators
On the Fourier cosine—Kontorovich-Lebedev generalized convolution transforms
We deal with several classes of integral transformations of the form where is an operator. In case is the identity operator, we obtain several operator properties on with weights for a generalized operator related to the Fourier cosine and the Kontorovich-Lebedev integral transforms. For a class of differential operators of infinite order, we prove the unitary property of these transforms on and define the inversion formula. Further, for an other class of differential operators of finite...
On the fractional integral of Weyl in Lp.