Omnipresent holomorphic operators and maximal cluster sets
On a binary relation between normal operators
The main goal of this paper is to clarify the antisymmetric nature of a binary relation ≪ which is defined for normal operators A and B by: A ≪ B if there exists an operator T such that for all Borel subset Δ of the complex plane ℂ, where and are spectral measures of A and B, respectively (the operators A and B are allowed to act in different complex Hilbert spaces). It is proved that if A ≪ B and B ≪ A, then A and B are unitarily equivalent, which shows that the relation ≪ is a partial order...
On a boundary value problem on the half-line for nonlinear two-dimensional delay differential systems
This article is concerned with a boundary value problem on the half-line for nonlinear two-dimensional delay differential systems. By the use of the Schauder-Tikhonov theorem, a result on the existence of solutions is obtained. Also, via the Banach contraction principle, another result concerning the existence and uniqueness of solutions is established. Moreover, these results are applied to the special case of ordinary differential systems and to a certain class of delay differential systems. Furthermore,...
On a Brezis-Nirenberg type problem.
On a cell decomposition for Hankel matrices and rational functions.
On a certain algorithm of eigenvalue localization for normal operators
On a certain approximation property for first-order abstract differential equations
On a certain class of always convergent sequences and the Rayleigh quotient iterations
On a certain class of nonstationary sequences in Hilbert space.
On a certain Volterra-Fredholm type integral equation.
On a characterization of reflexive Banach spaces
On a characterization of the Preisach model for hysteresis
On a class of absolutely p-summing operators
On a class of abstract degenerate fractional differential equations of parabolic type
In this paper, we investigate a class of abstract degenerate fractional differential equations with Caputo derivatives. We consider subordinated fractional resolvent families generated by multivalued linear operators, which do have removable singularities at the origin. Semi-linear degenerate fractional Cauchy problems are also considered in this context.
On a class of -contractions: hyperinvariant subspaces and intertwining operators.
On a class of diffeomorphisms defined by integro-differential operators
We study an integro-differential operator Φ: H̅¹ → L² of Fredholm type and give sufficient conditions for Φ to be a diffeomorphism. An application to functional equations is presented.
On a class of discontinuous operators in Hilbert spaces
We construct a class of discontinuous operators in infinite-dimensional separable Hilbert spaces, answering a natural question which arises in comparing a fixed point theorem of Altman and Shinbrot ([1], [4]) with its improvement obtained by Ricceri ([2], [3]).
On a class of elliptic differential operators degenerating at one point
On a class of functional differential equations having slowly varying solutions.
On a class of Hausdorff compact and GSG Banach spaces