On the spectral function of a normal operator
On the Spectral Kernel of Symmetric Extensions.
On the spectral multiplicity of a direct sum of operators
We calculate the spectral multiplicity of the direct sum T⊕ A of a weighted shift operator T on a Banach space Y which is continuously embedded in and a suitable bounded linear operator A on a Banach space X.
On the spectral properties of tensor products of linear operators in Banach spaces
On the spectral properties of translation operators in one-dimensional tubes
We study the spectral properties of some group of unitary operators in the Hilbert space of square Lebesgue integrable holomorphic functions on a one-dimensional tube (see formula (1)). Applying the Genchev transform ([2], [5]) we prove that this group has continuous simple spectrum (Theorem 4) and that the projection-valued measure for this group has a very explicit form (Theorem 5).
On the spectral radius of positive operators.
On the spectral radius of positive operators (Corrigendum).
On the spectral set of a solvable Lie algebra of operators.
On the spectral theory of pseudo-differential elliptic boundary problems
On the spectrum and eigenfunctions of the operator
On the spectrum and eigenfunctions of the Schrödinger operator with Aharonov–Bohm magnetic field.
On the spectrum of a morphism of quotient Hilbert spaces.
On the spectrum of a nonlinear operator
On the spectrum of a one-parameter strongly continous representation.
On the spectrum of multipliers in Bessel potential spaces
On the spectrum of non-selfadjoint differential operators.
On the spectrum of orthomorphisms and Barbashin operators.
On the spectrum of Robin Laplacian in a planar waveguide
We consider the Laplace operator in a planar waveguide, i.e. an infinite two-dimensional straight strip of constant width, with Robin boundary conditions. We study the essential spectrum of the corresponding Laplacian when the boundary coupling function has a limit at infinity. Furthermore, we derive sufficient conditions for the existence of discrete spectrum.
On the spectrum of singularly perturbed operators
On the spectrum of stochastic perturbations of the shift and Julia sets
We extend the Killeen-Taylor study [Nonlinearity 13 (2000)] by investigating in different Banach spaces (,c₀(ℕ),c(ℕ)) the point, continuous and residual spectra of stochastic perturbations of the shift operator associated to the stochastic adding machine in base 2 and in the Fibonacci base. For the base 2, the spectra are connected to the Julia set of a quadratic map. In the Fibonacci case, the spectrum is related to the Julia set of an endomorphism of ℂ².