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Related papers: Revisiting Korovkin-type Theorems in Banach Functi…

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We show that a mathematical version of the formal Chern-Simons functional integral of Witten for manifolds equipped with a reflection may be constructed in terms of a reflection positive functional, associated to the quadratic term in the…

Mathematical Physics · Physics 2024-06-19 Jonathan Weitsman

We prove an extrapolation of compactness theorem for operators on Banach function spaces satisfying certain convexity and concavity conditions. In particular, we show that the boundedness of an operator $T$ in the weighted Lebesgue scale…

Classical Analysis and ODEs · Mathematics 2024-05-31 Emiel Lorist , Zoe Nieraeth

These notes have the intent to introduce the study of the nonlinear aspects of operator space theory. We investigate some results on the nonlinear theory of Banach spaces which remain valid in the noncommutative case. In particular, we show…

Operator Algebras · Mathematics 2019-12-04 Bruno de Mendonça Braga , Thomas Sinclair

We prove a Logvinenko-Sereda Theorem for vector valued functions. That is, for an arbitrary Banach space $X$, all $p \in [1,\infty]$, all $\lambda \in (0,\infty)^d$, all $f \in L^p (\mathbb{R}^d ; X)$ with $\operatorname{supp} \mathcal{F} f…

Functional Analysis · Mathematics 2025-01-27 Clemens Bombach , Martin Tautenhahn

Starting with an integrable unitary representation of a locally compact group and its associated voice transform, coorbit theory describes the construction and investigation of the so-called coorbit spaces. A coorbit space consists of…

Functional Analysis · Mathematics 2024-01-24 Jan Zimmermann

There are two main aims of the paper. The first one is to extend the criterion for the precompactness of sets in Banach function spaces to the setting of quasi-Banach function spaces. The second one is to extend the criterion for the…

Functional Analysis · Mathematics 2017-01-11 António Caetano , Amiran Gogatishvili , Bohumír Opic

We introduce an operator valued Short-Time Fourier Transform for certain classes of operators with operator windows, and show that the transform acts in an analogous way to the Short-Time Fourier Transform for functions, in particular…

Functional Analysis · Mathematics 2023-06-08 Monika Dörfler , Franz Luef , Henry McNulty , Eirik Skrettingland

In this paper, using the concept of $A$-statistical convergence which is a regular (non-matrix) summability method, we obtain a general Korovkin type approximation theorem which concerns the problem of approximating a function $f$ by means…

Classical Analysis and ODEs · Mathematics 2007-05-23 Esra Erkus , Oktay Duman

We prove implicit function theorems for mappings on topological vector spaces over valued fields. In the real and complex cases, we obtain implicit function theorems for mappings from arbitrary (not necessarily locally convex) topological…

General Mathematics · Mathematics 2007-05-23 Helge Glockner

In this paper, the authors propose a new framework under which a theory of generalized Besov-type and Triebel-Lizorkin-type function spaces is developed. Many function spaces appearing in harmonic analysis fall under the scope of this new…

Classical Analysis and ODEs · Mathematics 2014-01-30 Yiyu Liang , Dachun Yang , Wen Yuan , Yoshihiro Sawano , Tino Ullrich

We study Bohr's theorem for vector valued holomorphic and operator valued pluriharmonic functions on complete Reinhardt domains in $\mathbb{C}^n$. Using invariants from local Banach space theory, we show that the associated Bohr radius is…

Complex Variables · Mathematics 2025-12-11 Himadri Halder

The purpose of the present work is to treat a new notion related to linear dynamics, which can be viewed as a "localization" of the notion of hypercyclicity. In particular, let $T$ be a bounded linear operator acting on a Banach space $X$…

Functional Analysis · Mathematics 2009-03-12 George Costakis , Antonios Manoussos

In this paper we obtain some practical criteria to bound the multiplication operator in Sobolev spaces with respect to measures in curves. As a consequence of these results, we characterize the weighted Sobolev spaces with bounded…

Functional Analysis · Mathematics 2008-06-02 José M. Rodríguez , José M. Sigarreta

The object of this paper is to prove a version of the Beurling-Helson-Lowdenslager invariant subspace theorem for operators on certain Banach spaces of functions on a multiply connected domain in the complex plane. The norms for these…

Functional Analysis · Mathematics 2016-07-06 Yanni Chen , Don Hadwin , Zhe Liu , Eric Nordgren

We introduce the so-called Bishop-Phelps-Bollob\'as property for positive functionals, a particular case of the Bishop-Phelps-Bollob\'as property for positive operators. First we show a version of the Bishop-Phelps-Bollob\'as theorem for…

Functional Analysis · Mathematics 2021-06-11 M. D. Acosta , M. Soleimani-Mourchehkhorti

In this paper, we establish a suitable version of the Hahn-Banach theorem within the framework of Colombeau spaces, a class of spaces used to model generalized functions. Our approach addresses the case where maps are defined…

Functional Analysis · Mathematics 2024-10-14 Djamel eddine Kebiche , Paolo Giordano

In this paper, we first study some elementary properties of a typical positive contraction on $\ell_q$ for the Strong Operator Topology and the Strong* Operator Topology. Using these properties, we prove that a typical positive contraction…

Functional Analysis · Mathematics 2025-11-25 Valentin Gillet

In this paper we recontextualize the theory of matrix weights within the setting of Banach lattices. We define an intrinsic notion of directional Banach function spaces, generalizing matrix weighted Lebesgue spaces. Moreover, we prove an…

Functional Analysis · Mathematics 2025-09-01 Zoe Nieraeth

In this note the Choquet type operators are introduced, in connection to Choquet's theory of integrability with respect to a not necessarily additive set function. Based on their properties, a quantitative estimate for the nonlinear…

Classical Analysis and ODEs · Mathematics 2021-04-14 Sorin G. Gal , Constantin P. Niculescu

In the present paper we establish a fixed point result of Krasnoselskii type for the sum $A+B$, where $A$ and $B$ are continuous maps acting on locally convex spaces. Our results extend previous ones. We apply such results to obtain strong…

Functional Analysis · Mathematics 2007-05-23 Cleon S. Barroso , Eduardo V. Teixeira