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Related papers: Extensions of an $AC(\sigma)$ functional calculus

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We study pairs of Banach spaces $(X,Y)$, with $Y\subset X$, for which the thesis of Sobczyk's theorem holds, namely, such that every bounded $c_0$-valued operator defined in $Y$ extends to $X$. We are mainly concerned with the case when $X$…

Functional Analysis · Mathematics 2013-02-27 Claudia Correa , Daniel V. Tausk

In this paper we provide some extension results for n-cyclically monotone operators in reflexive Banach spaces by making use of the Fenchel duality. In this way we give a positive answer to a question posed by Bauschke and Wang in [4].

Optimization and Control · Mathematics 2009-12-04 Radu Ioan Bot , Erno Robert Csetnek

In this paper, we study integral functionals defined on spaces of functions with values on general (non-separable) Banach spaces. We introduce a new class of integrands and multifunctions for which we obtain measurable selection results.…

Optimization and Control · Mathematics 2022-08-10 Juan Guillermo Garrido , Pedro Pérez-Aros , Emilio Vilches

We introduce a modified version of the Whitney extension operators for collections of functions from a closed subset of $\mathbb{R}^n$ into scales of Banach spaces with smoothing operators. We prove an extension theorem for collections…

Functional Analysis · Mathematics 2021-02-12 Pietro Baldi

We give a direct non-abstract proof of the Spectral Mapping Theorem for the Helffer-Sj\"ostrand functional calculus for linear operators on Banach spaces with real spectra and consequently give a new non-abstract direct proof for the…

Spectral Theory · Mathematics 2012-07-16 Narinder S Claire

We show that any bounded operator $T$ on a separable, reflexive, infinite-dimensional Banach space $X$ admits a rank one perturbation which has an invariant subspace of infinite dimension and codimension. In the non-reflexive spaces, we…

Functional Analysis · Mathematics 2012-08-30 Alexey I. Popov , Adi Tcaciuc

While the theory of matrix-weighted function spaces is well established, the majority of previous results in the infinite-dimensional operator-valued setting deal with "no go" theorems, showing the impossibility of some prospective…

Functional Analysis · Mathematics 2026-04-21 Tuomas P. Hytönen , Yinqin Li , Dachun Yang , Wen Yuan

On each nonreflexive Banach space X there exists a positive continuous convex function f such that 1/f is not a d.c. function (i.e., a difference of two continuous convex functions). This result together with known ones implies that X is…

Functional Analysis · Mathematics 2007-06-06 P. Holicky , O. Kalenda , L. Vesely , L. Zajicek

We build on the work by Davies, extending the Helffer-Sj\"ostrand Functional Calculus domain for semi-bounded operators on Banach spaces given a priori controlled growth of the resolvents. We employ Seeley's Extension Theorem to extend…

Spectral Theory · Mathematics 2007-05-23 Narinder Claire

The main objects of study in this paper are those functionals that are analytic in the sense that they annihilate the non-commutative disc algebra. In the classical univariate case, a theorem of F. and M. Riesz implies that such functionals…

Operator Algebras · Mathematics 2021-04-07 Raphaël Clouâtre , Robert T. W. Martin , Edward J. Timko

Let S be a dense sub-semigroup of the positive real numbers, and let X be a separable, reflexive Banach space. This note contains a proof that every weakly continuous contractive semigroup of operators on X over S can be extended to a…

Functional Analysis · Mathematics 2009-03-21 Eliahu Levy , Orr Shalit

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

We study two classes of extension problems, and their interconnections: (i) Extension of positive definite (p.d.) continuous functions defined on subsets in locally compact groups $G$; (ii) In case of Lie groups, representations of the…

Functional Analysis · Mathematics 2015-07-10 Palle Jorgensen , Steen Pedersen , Feng Tian

Transfer operators and Ruelle zeta functions for super-continuous functions on one-sided topological Markov shifts are considered. For every super-continuous function, we construct a Banach space on which the associated transfer operator is…

Dynamical Systems · Mathematics 2020-11-03 Katsukuni Nakagawa

Let $V\subseteq W$ be two operator spaces. Arveson-Wittstock-Hahn-Banach theorem asserts that every completely contractive map $\varphi:V\to \mathcal{B}(H)$ has a completely contractive extension $\tilde{\varphi}:W\to \mathcal{B}(H)$, where…

Operator Algebras · Mathematics 2013-03-15 Jung-Jin Lee

We exhibit a general class of unbounded operators in Banach spaces which can be shown to have the single-valued extension property, and for which the local spectrum at suitable points can be determined. We show that a local spectral radius…

Spectral Theory · Mathematics 2023-05-31 Nils Byrial Andersen , Marcel de Jeu

In this paper, a new axiomatization for unbounded functional calculi is proposed and the associated theory is elaborated comprising, among others, uniqueness and compatibility results and extension theorems of algebraic and topological…

Functional Analysis · Mathematics 2020-09-11 Markus Haase

For a function defined on an arbitrary subset of a Riemann surface, we give conditions which allow the function to be extended conformally. One folkloric consequence is that two common definitions of an analytic arc in ${\mathbb C}$ are…

Complex Variables · Mathematics 2014-06-16 P. M. Gauthier , V. Nestoridis

For Banach spaces of analytic functions on the disc for which the polynomials are dense and their pointt evaluations continuous, we prove the following: If they contain a function such that the limit superior of its modulus is infinite…

Complex Variables · Mathematics 2025-10-14 Hector N. Salas

The $S$-functional calculus is based on the theory of slice hyperholomorphic functions and it defines functions of $n$-tuples of not necessarily commuting operators or of quaternionic operators. This calculus relays on the notion of…

Functional Analysis · Mathematics 2016-09-21 Fabrizio Colombo , Jonathan Gantner