A survey of some recent inequalities for the norm and numerical radius of operators in Hilbert spaces.
A survey on dilations of projective isometric representations.
A survey on the numerical index of a Banach space.
A survey on the Weierstrass approximation theorem.
A symbolic calculus and a parametrix construction for pseudodifferential operators with non-smooth negative definite symbols.
A Szegö type property for two doubly commuting contractions
A tauberian theorem in quantum mechanical inverse scattering theory
A theorem of Rolewicz's type for measurable evolution families in Banach spaces.
A theorem on "localized" self-adjointness of Schrödinger operators with potentials.
A theory on perturbations of the Dirac operator.
A topological characterization of the product of two closed operators
The purpose of this work is to give a topological condition for the usual product of two closed operators acting in a Hilbert space to be closed.
A trace inequality for functions of triangular Hilbert-Schmidt operators
A Two Hilbert Space Scattering Theorem.
A unified analysis of elliptic problems with various boundary conditions and their approximation
We design an abstract setting for the approximation in Banach spaces of operators acting in duality. A typical example are the gradient and divergence operators in Lebesgue-Sobolev spaces on a bounded domain. We apply this abstract setting to the numerical approximation of Leray-Lions type problems, which include in particular linear diffusion. The main interest of the abstract setting is to provide a unified convergence analysis that simultaneously covers (i) all usual boundary conditions, (ii)...
A unitary invariant for pairs of self-adjoint operators.
A useful algebra for functional calculus
We show that some unital complex commutative LF-algebra of -tempered functions on (M. Hemdaoui, 2017) equipped with its natural convex vector bornology is useful for functional calculus.
A way of estimating the convergence rate of the Fourier method for PDE of hyperbolic type
The Fourier expansion in eigenfunctions of a positive operator is studied with the help of abstract functions of this operator. The rate of convergence is estimated in terms of its eigenvalues, especially for uniform and absolute convergence. Some particular results are obtained for elliptic operators and hyperbolic equations.
Abelian ergodic theorems for contraction semigroups
About one high-order linear equation of mixed type.
About some linear operators.