Note on operators produced by sesquilinear forms
Note on pointwise contractive projections.
Note on some results for asymptotically pseudocontractive mappings and asymptotically nonexpansive mappings.
Note on spectral theory of nonlinear operators: Extensions of some surjectivity theorems of Fučík and Nečas
Note on the Fredholm alternative for nonlinear operators
Note on the paper: interior proximal method for variational inequalities on non-polyhedral sets
In this paper we clarify that the interior proximal method developed in [6] (vol. 27 of this journal) for solving variational inequalities with monotone operators converges under essentially weaker conditions concerning the functions describing the "feasible" set as well as the operator of the variational inequality.
Note on the spectral inclusion theorem for Toeplitz operators
Note on the strong maximal operator
Note on weakly inward mappings
The Nielsen fixed point theory is used to show several results for certain operator equations involving weakly inward mappings.
Note to the paper by R. Hempel, A. M. Hinz, and H. Kalf: On the Essential Spectrum of Schrödinger Operators with Spherically Symmetric Potentials.
Notes about the hypercyclicity criterion
Notes on Analytic Convoluted -semigroups
Notes on commutator on the variable exponent Lebesgue spaces
We obtain the factorization theorem for Hardy space via the variable exponent Lebesgue spaces. As an application, it is proved that if the commutator of Coifman, Rochberg and Weiss is bounded on the variable exponent Lebesgue spaces, then is a bounded mean oscillation (BMO) function.
Notes on q-deformed operators
The paper concerns operators of deformed structure like q-normal and q-hyponormal operators with the deformation parameter q being a positive number different from 1. In particular, an example of a q-hyponormal operator with empty spectrum is given, and q-hyponormality is characterized in terms of some operator inequalities.
Notes on some spectral radius and numerical radius inequalities
We prove numerical radius inequalities for products, commutators, anticommutators, and sums of Hilbert space operators. A spectral radius inequality for sums of commuting operators is also given. Our results improve earlier well-known results.
Notes on the Fučík spectrum and the mixed boundary value problem
The paper is devoted to the study of the properties of the Fučík spectrum. In the first part, we analyse the Fučík spectra of the problems with one second order ordinary differential equation with Dirichlet, Neumann and mixed boundary conditions and we present the explicit form of nontrivial solutions. Then, we discuss the problem with two second order differential equations with mixed boundary conditions. We show the relation between the Dirichlet boundary value problem and mixed boundary value...
Notes on the propagators of evolution equations.
Notes on the Taylor joint spectrum of commuting operators
Notes on unbounded Toeplitz operators in Segal-Bargmann spaces
Relations between different extensions of Toeplitz operators are studied. Additive properties of closed Toeplitz operators are investigated, in particular necessary and sufficient conditions are given and some applications in case of Toeplitz operators with polynomial symbols are indicated.
Nouvelles formulations intégrales pour les problèmes de diffraction d’ondes
We present an integral equation method for solving boundary value problems of the Helmholtz equation in unbounded domains. The method relies on the factorisation of one of the Calderón projectors by an operator approximating the exterior admittance (Dirichlet to Neumann) operator of the scattering obstacle. We show how the pseudo-differential calculus allows us to construct such approximations and that this yields integral equations without internal resonances and being well-conditioned at all frequencies....