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Let $\mathcal A$ be a separable Banach algebra, $G$ be a locally compact Hausdorff group and $1< p<\infty$. In this paper, we first provide a necessary and sufficient condition, for which $L^p(G,\mathcal A)$ is a Banach algebra, under…

Functional Analysis · Mathematics 2022-06-16 Fatemeh Abtahi , Mitra Amiri , Ali Rejali

We give a unified approach to handle the problem of extending functions with values in a locally convex Hausdorff space $E$ over a field $\mathbb{K}$, which have weak extensions in a space $\mathcal{F}(\Omega,\mathbb{K})$ of scalar-valued…

Functional Analysis · Mathematics 2023-04-05 Karsten Kruse

We extend an example of B. Aupetit, which illustrates spectral discontinuity for operators on an infinite dimensional separable Hilbert space, to a general spectral discontinuity result in abstract Banach algebras. This can then be used to…

Functional Analysis · Mathematics 2018-08-10 Rudi Brits

Given any continuous self-map f of a Banach space E over K (where K is R or C) and given any point p of E, we define a subset sigma(f,p) of K, called spectrum of f at p, which coincides with the usual spectrum sigma(f) of f in the linear…

Spectral Theory · Mathematics 2010-05-12 Alessandro Calamai , Massimo Furi , Alfonso Vignoli

Let $X(\mathbb{R})$ be a separable Banach function space such that the Hardy-Littlewood maximal operator is bounded $X(\mathbb{R})$ and on its associate space $X'(\mathbb{R})$. The algebra $C_X(\dot{\mathbb{R}})$ of continuous Fourier…

Functional Analysis · Mathematics 2021-03-26 Alexei Karlovich , Eugene Shargorodsky

Suppose that $B$ is a $G$-Banach algebra over $\mathbb{F} = \mathbb{R}$ or $\mathbb{C}$, $X$ is a finite dimensional compact metric space, $\zeta : P \to X$ is a standard principal $G$-bundle, and $A_\zeta = \Gamma (X, P \times_G B)$ is the…

Operator Algebras · Mathematics 2012-01-12 Emmanuel Dror Farjoun , Claude L. Schochet

In this paper, we introduce and analyze multidimensional vector-valued Laplace transform of functions with values in sequentially complete locally convex spaces. A great number of our results seem to be new even for the functions with…

Functional Analysis · Mathematics 2025-06-25 Marko Kostic

We are interested in Beurling spectrum of $\mathbb X-$valued functions with application in functional delay differential equations.

General Mathematics · Mathematics 2013-04-03 Dang Vu Giang

For a fixed Banach operator ideal $\mathcal A$, we use the notion of $\mathcal A$-compact sets of Carl and Stephani to study $\mathcal A$-compact polynomials and $\mathcal A$-compact holomorphic mappings. Namely, those mappings $g\colon…

Functional Analysis · Mathematics 2016-01-26 Pablo Turco

Our principal result is the following. Let $X$ and $Y$ be Banach spaces, let $G$ be a locally compact abelian group, and let $K$ be an operator valued kernel defined on $G$ with values in the space of bounded linear operators from $X$ to…

Classical Analysis and ODEs · Mathematics 2020-03-19 E. Berkson , T. A. Gillespie , J. L. Torrea

Let $X$ and $Y$ be compact Hausdorff spaces, $E$ and $F$ be real or complex Banach spaces, and $A(X,E)$ be a subspace of $C(X,E)$. In this paper we study linear operators $S,T: A(X,E) \lo C(Y,F)$ which are jointly separating, in the sense…

Functional Analysis · Mathematics 2018-05-01 Z. Pourghobadi , M. Najafi Tavani , F. Sady

We systematically derive general properties of continuous and holomorphic functions with values in closed operators, allowing in particular for operators with empty resolvent set. We provide criteria for a given operator-valued function to…

Functional Analysis · Mathematics 2015-06-17 Jan Dereziński , Michał Wrochna

This paper presents abstract harmonic analysis foundations for structure of covariant function algebras of invariant characters of normal subgroups. Suppose that $G$ is a locally compact group and $N$ is a closed normal subgroup of $G$. Let…

Functional Analysis · Mathematics 2024-01-23 Arash Ghaani Farashahi

We prove a commutative Gelfand--Naimark type theorem, by showing that the set $C_s(X)$ of continuous bounded (real or complex valued) functions with separable support on a locally separable metrizable space $X$ (provided with the supremum…

Functional Analysis · Mathematics 2015-06-26 M. R. Koushesh

Let A be a closed subalgebra of a C*-algebra, that is a closed algebra of Hilbert space operators. We generalize to such operator algebras $A$ several key theorems and concepts from the theory of classical function algebras. In particular…

Operator Algebras · Mathematics 2020-03-02 David P. Blecher , Louis E. Labuschagne

In the recent paper \cite{Aza:19} D Azagra studies the global shape of continuous convex functions defined on a Banach space $X$. More precisely, when $X$ is separable, it is shown that for every continuous convex function…

Functional Analysis · Mathematics 2020-01-22 Constantin Zalinescu

In this paper we give a simple proof of inequalities of integrals of functions which are the composition of nonnegative continous convex functions on a vector space ${\bf R}^m$ and vector-valued functions in a weakly compact subset of a…

Functional Analysis · Mathematics 2007-08-27 Zhenglu Jiang , Xiaoyong Fu , Hongjiong Tian

Let $X$ be a locally compact Hausdorff space, let $A$ be a partially ordered algebra, and let $\pi\colon \mathrm{C}_{\mathrm c}(X)\to A$ be a positive algebra homomorphism. Under conditions on $A$ that are satisfied in a good number of…

Functional Analysis · Mathematics 2024-08-01 Marcel de Jeu , Xingni Jiang

We introduce Banach spaces of vector-valued random variables motivated from mathematical finance. So-called risk functionals are defined in a natural way on these Banach spaces and it is shown that these functionals are Lipschitz…

Functional Analysis · Mathematics 2018-11-14 Thomas Kalmes , Alois Pichler

In the present note we introduce tame functionals on Banach algebras. A functional $f \in A^*$ on a Banach algebra $A$ is tame if the naturally defined linear operator $A \to A^*, a \mapsto f \cdot a$ factors through Rosenthal Banach spaces…

Functional Analysis · Mathematics 2017-10-04 Michael Megrelishvili