On Co-Semigroups of Lattice Homomorphisms on a Banach Lattice.
On cyclicity in weighted Dirichlet spaces.
On where has infinitely many “bumps”
On decomposably regular operators.
On decomposition of pairs of commuting isometries
A review of known decompositions of pairs of isometries is given. A new, finer decomposition and its properties are presented.
On derivations and crossed homomorphisms
We discuss some results about derivations and crossed homomorphisms arising in the context of locally compact groups and their group algebras, in particular, L¹(G), the von Neumann algebra VN(G) and actions of G on related algebras. We answer a question of Dales, Ghahramani, Grønbæk, showing that L¹(G) is always permanently weakly amenable. Then we show that for some classes of groups (e.g. IN-groups) the homology of L¹(G) with coefficients in VN(G) is trivial. But this is no longer true, in general,...
On derivations over rings of triangular matrices
On determination of eigenvalues and eigenvectors of selfadjoint operators
Two simple methods for approximate determination of eigenvalues and eigenvectors of linear self-adjoint operators are considered in the following two cases: (i) lower-upper bound of the spectrum of is an isolated point of ; (ii) (not necessarily an isolated point of with finite multiplicity) is an eigenvalue of .
On differences of heat semigroups
On differences of Riesz homomorphisms.
On differences of self-adjoint semigroups
On Dominant Operators.
On dyadic spaces and almost Milyutin spaces
On eigenfunction expansions and scattering theory.
On Erb's uncertainty principle
We improve a result of Erb, concerning an uncertainty principle for orthogonal polynomials. The proof uses numerical range and a decomposition of some multiplication operators as a difference of orthogonal projections.
On essential norm of the Neumann operator
One of the classical methods of solving the Dirichlet problem and the Neumann problem in is the method of integral equations. If we wish to use the Fredholm-Radon theory to solve the problem, it is useful to estimate the essential norm of the Neumann operator with respect to a norm on the space of continuous functions on the boundary of the domain investigated, where this norm is equivalent to the maximum norm. It is shown in the paper that under a deformation of the domain investigated by a diffeomorphism,...
On Essential Self-Adjointness for Singular Elliptic Differential Operators.
On essential selfadjointness of the Weyl quantized relativistic Hamiltonian.
On estimates for spectral projections of perturbed selfadjoint operators.
On extended eigenvalues and extended eigenvectors of truncated shift
In this paper we consider the truncated shift operator Su on the model space K2u := H2 θ uH2. We say that a complex number λ is an extended eigenvalue of Su if there exists a nonzero operator X, called extended eigenvector associated to λ, and satisfying the equation SuX = λXSu. We give a complete description of the set of extended eigenvectors of Su, in the case of u is a Blaschke product..