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Related papers: Extension operators via semigroups

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We study properties of the topological space of composition operators on the Banach algebra of bounded functions on an unbounded, locally finite metric space in the operator norm topology and essential norm topology. Moreover, we…

Functional Analysis · Mathematics 2022-07-26 Robert F. Allen , Whitney George , Matthew A. Pons

We establish a spectral characterization theorem for the operators on complex Hilbert spaces of arbitrary dimensions that attain their norm on every closed subspace. The class of these operators is not closed under addition. Nevertheless,…

Functional Analysis · Mathematics 2016-07-13 Satish K. Pandey , Vern I. Paulsen

We study properties of continuous semi-homogeneous operators of degree $k$ via various functions (e.g. measures of noncompactness) on all bounded subsets of a Banach space. We prove necessary and sufficient conditions for these functions to…

Functional Analysis · Mathematics 2015-08-19 Nina A. Erzakova

In this paper we study some basic properties of bicomplex linear operators on bicomplex Hilbert spaces. Further we discuss some applications of Hahn-Banach theorem on bicomplex Banach modules. We also introduce and discuss some bicomplex…

Functional Analysis · Mathematics 2014-06-02 Romesh Kumar , Kulbir Singh

We consider a linear symmetric operator in a Hilbert space that is neither bounded from above nor from below, admits a block decomposition corresponding to an orthogonal splitting of the Hilbert space and has a variational gap property…

Spectral Theory · Mathematics 2024-09-13 Jean Dolbeault , Maria J. Esteban , Eric Séré

The epsilon-enlargement of a maximal monotone operator is a construct similar to the Br{\o}ndsted and Rocakfellar epsilon-subdifferential enlargement of the subdifferential. Like the epsilon-subdifferential, the epsilon-enlargement of a…

Functional Analysis · Mathematics 2010-05-25 B. F. Svaiter

We study ordinal-indexed, multi-layer iterations of bounded operator transforms and prove convergence to spectral/ergodic projections under functional-calculus hypotheses. For normal operators on Hilbert space and polynomial or holomorphic…

Functional Analysis · Mathematics 2025-08-11 Faruk Alpay , Taylan Alpay , Hamdi Alakkad

The main result of this paper states that if a Banach space X has the property that every bounded operator from an arbitrary subspace of X into an arbitrary Banach space of cotype 2 extends to a bounded operator on X, then…

Functional Analysis · Mathematics 2007-05-23 Peter G. Casazza , Niels Jorgen Nielsen

In this paper we introduce a class of pseudo-dissipative holomorphic maps which contains, in particular, the class of infinitesimal generators of semigroups of holomorphic maps on the unit ball of a complex Banach space. We give a growth…

Complex Variables · Mathematics 2013-04-25 Filippo Bracci , Mark Elin , David Shoikhet

We introduce and study the notion of generating operators as those norm-one operators $G\colon X\longrightarrow Y$ such that for every $0<\delta<1$, the set $\{x\in X\colon \|x\|\leq 1,\ \|Gx\|>1-\delta\}$ generates the unit ball of $X$ by…

Functional Analysis · Mathematics 2023-06-06 Vladimir Kadets , Miguel Martin , Javier Meri , Alicia Quero

The class of strictly singular operators originating from the dual of a separable Banach space is written as an increasing union of $\omega_1$ subclasses which are defined using the Schreier sets. A question of J. Diestel, of whether a…

Functional Analysis · Mathematics 2008-06-03 G. Androulakis , K. Beanland

We show that the space of bounded and linear operators between spaces of continuous functions on compact Hausdorff topological spaces has the Bishop-Phelps-Bollob\'as property. A similar result is also proved for the class of compact…

We study different aspects of the connections between local theory of Banach spaces and the problem of the extension of bilinear forms from subspaces of Banach spaces. Among other results, we prove that if $X$ is not a Hilbert space then…

Functional Analysis · Mathematics 2015-05-28 J. M. F. Castillo , A. Defant , R. García , D. Pérez-García , J. Suárez

This current article aims to study a new subclass of meromorphic functions with positive coefficients by reconstructing a new operator in the punctured open disc. Also, some geometric properties are considered and investigated, such results…

Complex Variables · Mathematics 2024-08-16 Ali H. Maran , Abdul Rahman S. Juma , Raheam A. Al-Saphory

We study multiplication operators on the weighted Banach spaces of an infinite tree. We characterize the bounded and the compact operators, as well as determine the operator norm. In addition, we determine the spectrum of the bounded…

Functional Analysis · Mathematics 2022-07-27 Robert F. Allen , Isaac Sundberg

An algebra extension A | B is right depth two if its tensor-square A\otimes_B A is in the Dress category Add A as A-B-bimodules. We consider necessary conditions for right, similarly left, D2 extensions in terms of partial A-invariance of…

Quantum Algebra · Mathematics 2007-05-23 Lars Kadison

For every closed subset $X$ of a stratifiable [resp. metrizable] space $Y$ we construct a positive linear extension operator $T:R^{X\times X}\to R^{Y\times Y}$ preserving constant functions, bounded functions, continuous functions,…

General Topology · Mathematics 2012-02-08 Taras Banakh , Czeslaw Bessaga

Let X and Y be complex Banach spaces, B_X be the open unit ball of X and HL(B_X,Y) be the Banach space of all holomorphic Lipschitz maps f:B_X->Y such that f(0)=0, endowed with the Lipschitz norm. Given a Banach operator ideal A, we use the…

Functional Analysis · Mathematics 2025-11-25 A. Jiménez-Vargas , D. Ruiz-Casternado

We present some results related to Hahn-Banach extension theorem for linear operators on asymmetric normed spaces. L. Nachbin, Trans. Amer. Math. Soc. 68 (1950), proved that a Banach space has the extension property for linear operators (a…

Functional Analysis · Mathematics 2024-12-17 S. Cobzaş

The paper makes the first steps into the study of extensions ("twisted sums") of noncommutative $L^p$-spaces regarded as Banach modules over the underlying von Neumann algebra $\mathcal M$. Our approach combines Kalton's description of…

Operator Algebras · Mathematics 2016-02-02 Félix Cabello Sánchez , Jesús M. F. Castillo , Stanislaw Goldstein , Jesús Suárez