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Related papers: The Ces\`aro operator in weighted $\ell_1$ spaces

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In this article, we consider the singular value asymptotics of compositions of compact linear operators mapping in the real Hilbert space of quadratically integrable functions over the unit interval. Specifically, the composition is given…

Numerical Analysis · Mathematics 2024-01-23 Yu Deng , Hans-Jürgen Fischer , Bernd Hofmann

We describe holomorphic functions and fractional powers of Ces\'{a}ro operators in $L^2(\mathbb{R})$, $L^2(\mathbb{R}_+)$, and $L^2[0,1]$. Logarithms of Ces\'{a}ro operators are introduced as well and their spectral properties are studied.…

Functional Analysis · Mathematics 2024-11-26 Adolf Mirotin

It is proved that every operator from a weak$^*$-closed subspace of $\ell_1$ into a space $C(K)$ of continuous functions on a compact Hausdorff space $K$ can be extended to an operator from $\ell_1$ to $C(K)$.

Functional Analysis · Mathematics 2009-09-25 William B. Johnson , M. Zippin

Let $\mu$ be a finite positive Borel measure on the interval $[0, 1)$ and $f(z)=\sum_{n=0}^{\infty}a_{n}z^{n} \in H(\mathbb{D})$. The Ces\`aro-like operator is defined by $$ \mathcal {C}_{\mu}…

Functional Analysis · Mathematics 2023-05-08 Pengcheng Tang

This paper explores various classes of invariant subspaces of the classical Ces\`{a}ro operator $C$ on the Hardy space $H^2$. We provide a new characterization of the finite co-dimensional $C$-invariant subspaces, based on earlier work of…

Functional Analysis · Mathematics 2023-11-28 Eva A. Gallardo-Gutierrez , Jonathan R. Partington , William T. Ross

We consider the composition of operators with non-closed range in Hilbert spaces and how the nature of ill-posedness is affected by their composition. Specifically, we study the \mbox{Hausdorff-,} Ces\`{a}ro-, integration operator, and…

Functional Analysis · Mathematics 2024-05-17 Stefan Kindermann , Bernd Hofmann

We derive faithful inclusions of C*-algebras from a coend-type construction in unitary tensor categories. This gives rise to different potential notions of discreteness for an inclusion in the non-irreducible case, and provides a unified…

Operator Algebras · Mathematics 2026-01-06 Lucas Hataishi , Roberto Hernández Palomares

In this paper we solve a long standing problem about the bilinear $T1$ theorem to characterize the (weighted) compactness of bilinear Calder\'{o}n-Zygmund operators. Let $T$ be a bilinear operator associated with a standard bilinear…

Classical Analysis and ODEs · Mathematics 2024-07-31 Mingming Cao , Honghai Liu , Zengyan Si , Kôzô Yabuta

We study several notions of boundedness for operators. It is known that any power bounded operator is absolutely Ces\`aro bounded and strong Kreiss bounded (in particular, uniformly Kreiss bounded). The converses do not hold in general. In…

Functional Analysis · Mathematics 2017-06-13 Teresa Bermúdez , Antonio Bonilla , Vladimir Müller , Alfredo Peris

In this article we study the Ces\`{a}ro operator $$ \mathcal{C}(f)(z)=\frac{1}{z}\int_{0}^{z}f(\zeta)\,d\zeta, $$ and its companion operator $\mathcal{T}$ on Hardy spaces of the upper half plane. We identify $\mathcal{C}$ and $\mathcal{T}$…

Complex Variables · Mathematics 2010-06-09 Athanasios G. Arvanitidis , Aristomenis G. Siskakis

In this paper, we introduce and investigate the notion of the Ces\'aro operator $C_{\mathscr T}$ on a rooted directed tree $\mathscr T.$ When $\mathscr T$ is the rooted tree with no branching vertex, then $C_{\mathscr T}$ is unitarily…

Functional Analysis · Mathematics 2025-12-08 Mankunikuzhiyil Abhinand , Sameer Chavan , Sophiya S. Dharan , Thankarajan Prasad

We consider $\ell^r$ extensions of Calderon-Zygmund operators on weighted spaces $L^p(w)$ with $w$ an $A_p$ weight and $1 < p < \infty$. We give quantitative estimates of these operators' norm in terms of a given weight's $A_p$…

Classical Analysis and ODEs · Mathematics 2012-10-29 James Scurry

In this paper we prove weighted $\ell^p$-inequalities for variation and oscillation operators defined by semigroups of operators associated with discrete Jacobi operators. Also, we establish that certain maximal operators involving sums of…

Classical Analysis and ODEs · Mathematics 2023-02-06 Jorge J. Betancor , Marta De León-Contreras

This paper explores a version of the classical Ces`aro integral operator for the Lebesgue space L2(0, 1) where we discuss its norm, adjoint, spectral properties, and invariant subspaces. An important tool will be semigroups of weighted…

Functional Analysis · Mathematics 2026-04-24 Anil Belli , Ugur Gul , William T. Ross , Aristomenis G. Siskakis

Let $C_\varphi$ be a composition operator acting on the Hardy space of the unit disc $H^p$ ($1\leq p < \infty$), which is embedded in a $C_0$-semigroup of composition operators $\mathcal{T}=(C_{\varphi_t})_{t\geq 0}.$ We investigate whether…

Functional Analysis · Mathematics 2024-06-28 F. Javier González-Doña

In this paper, we characterize supercyclic weighted composition operators on a large class of solid Banach function spaces, in particular on Lebesgue, Orlicz and Morrey spaces. Also, we characterize supercyclic weighted composition…

Functional Analysis · Mathematics 2025-12-09 Stefan Ivkovic

Let $\mathcal{T}^*$ be the semi-group maximal function associated to the Schr\"odinger operator $-\Delta+V(x)$ with $V$ satisfying an appropriate reverse H\"{o}lder inequality. In this paper, we show that the commutator of $\mathcal{T}^*$…

Classical Analysis and ODEs · Mathematics 2021-02-04 Shifen Wang , Qingying Xue

We study power boundedness and related properties such as mean ergodicity for (weighted) composition operators on function spaces defined by local properties. As a main application of our general approach we characterize when (weighted)…

Functional Analysis · Mathematics 2019-03-27 Thomas Kalmes

For the weight function $\prod_{i=1}^{d+1}|x_i|^{2\k_i}$ on the unit sphere, sharp local estimates of the orthogonal projection operators are obtained and used to prove the convergence of the Ces\`aro $(C,\delta)$ means in the weighted…

Classical Analysis and ODEs · Mathematics 2007-06-07 Feng Dai , Yuan Xu

The discrete Ces\`aro operator $ C $ acts continuously in various classical Banach sequence spaces within $ \mathbb{C}^{\mathbb{N}}.$ For the coordinatewise order, many such sequence spaces $ X $ are also complex Banach lattices (eg. $c_0,…

Functional Analysis · Mathematics 2019-05-21 José Bonet , Werner J. Ricker