Invertibility of matrix Wiener--Hopf plus Hankel operators with APW Fourier symbols.
Invertibility of the commutator of an element in a C*-algebra and its Moore-Penrose inverse
We study the subset in a unital C*-algebra composed of elements a such that is invertible, where denotes the Moore-Penrose inverse of a. A distinguished subset of this set is also investigated. Furthermore we study sequences of elements belonging to the aforementioned subsets.
Invitation to functional means: some problems. (Invitaion to functional means some problems.)
Isolated points of spectrum of k-quasi-*-class A operators
Let T be a bounded linear operator on a complex Hilbert space H. In this paper we introduce a new class, denoted *, of operators satisfying where k is a natural number, and we prove basic structural properties of these operators. Using these results, we also show that if E is the Riesz idempotent for a non-zero isolated point μ of the spectrum of T ∈ *, then E is self-adjoint and EH = ker(T-μ) = ker(T-μ)*. Some spectral properties are also presented.
Isometric parts of operators and the critical exponent
Isometries in , generating functions and extremal problems
Isometries on Irreducible Triangular Operator Algebras.
Isomorphic classification and lifting theorems for spaces of differentiable functions with Lipschitz conditions
Isomorphic Schauder decompositions in certain Banach spaces
We extend a theorem of Kato on similarity for sequences of projections in Hilbert spaces to the case of isomorphic Schauder decompositions in certain Banach spaces. To this end we use ℓψ-Hilbertian and ∞-Hilbertian Schauder decompositions instead of orthogonal Schauder decompositions, generalize the concept of an orthogonal Schauder decomposition to the case of Banach spaces and introduce the class of Banach spaces with Schauder-Orlicz decompositions. Furthermore, we generalize the notions of type,...
Iterated series and the Hellinger-Toeplitz theorem.
We show that an iterated double series condition due to Antosik implies the uniform convergence of the double series. An application of Antosik's condition is given to the derivation of a vector form of the Hellinger-Toeplitz theorem.
Iteration of Analytic Functions of Operators.
Iterations converging to distinct solutions of some nonlinear operator equations in Banach space.
Iterative refinement for approximate eigenelements of compact operators
Iterative solution of eigenvalue problems for normal operators
We will discuss Kellogg's iterations in eigenvalue problems for normal operators. A certain generalisation of the convergence theorem is shown.
Iterative solution of unstable variational inequalities on approximately given sets.