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Related papers: The non-resonant bilinear Hilbert--Carleson operat…

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Building on the (Rank I) LGC-methodology introduced by the second author and on the novel perspective employed in the time-frequency discretization of the non-resonant bilinear Hilbert--Carleson operator, we develop a new, versatile method…

Classical Analysis and ODEs · Mathematics 2023-08-22 Bingyang Hu , Victor Lie

For a closed densely defined operator $T$ from a Hilbert space $\mathfrak{H}$ to a Hilbert space $\mathfrak{K}$, necessary and sufficient conditions are established for the factorization of $T$ with a bounded nonnegative operator $X$ on…

Functional Analysis · Mathematics 2025-07-21 Yosra Barkaoui , Seppo Hassi

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

In this paper we introduce and prove some properties of $(\alpha;\beta)$-normal operators according to semi-Hilbertian space structures. Furthermore we s,ate various inequalities between the A-operator norm and A-numerical radius of…

Functional Analysis · Mathematics 2016-10-12 Abdelkader Benali , Ould Ahmed Mahmoud Sid Ahmed

We demonstrate and develop dyadic-probabilistic methods in connection with non-homogeneous bilinear operators, namely singular integrals and square functions. We develop the full non-homogeneous theory of bilinear singular integrals using a…

Classical Analysis and ODEs · Mathematics 2018-10-19 Henri Martikainen , Emil Vuorinen

We establish extrapolation of compactness for bilinear operators in the scale of weighted variable exponent Lebesgue spaces. First, we prove an abstract principle relying on the Cobos-Fern\'{a}ndez-Cabrera-Mart\'{i}nez theorem. Then, as an…

Classical Analysis and ODEs · Mathematics 2025-12-23 Spyridon Kakaroumpas , Stefanos Lappas

Several new improvements of the $A$-numerical radius inequalities for operators acting on a semi-Hilbert space, i.e., a space generated by a positive operator $A$, are proved. In particular, among other inequalities, we show that…

Functional Analysis · Mathematics 2021-01-05 Kais Feki

For each $ \alpha > 0 $, the $\alpha$-Bloch space is consisting of all analytic functions $f$ on the unit disk satisfying $ \sup_{|z|<1} (1-|z|^2)^\alpha |f'(z)| < + \infty.$ In this paper, we consider the following complex integral…

Functional Analysis · Mathematics 2020-04-23 Shankey Kumar , Swadesh Kumar Sahoo

In this paper, the $m-$order infinite dimensional Hilbert tensor (hypermatrix) is intrduced to define an $(m-1)$-homogeneous operator on the spaces of analytic functions, which is called Hilbert tensor operator. The boundedness of Hilbert…

Complex Variables · Mathematics 2022-02-09 Yisheng Song , Liqun Qi

We prove a plethora of boundedness property of the Adams type for bilinear fractional integral operators of the form $$B_{\alpha}(f,g)(x)=\int_{\mathbb{R}^{n}}\frac{f(x-y)g(x+y)}{|y|^{n-\alpha}}dy,\qquad 0<\alpha<n.$$ For $1<t\leq…

Classical Analysis and ODEs · Mathematics 2019-05-28 Qianjun He , Dunyan Yan

In this paper we study the Hilbert transformations over $L^2(\mathbb{R})$ and $L^2(\mathbb{T})$ from the viewpoint of symmetry. For a linear operator over $L^2(\mathbb{R})$ commutative with the ax+b group we show that the operator is of the…

Complex Variables · Mathematics 2017-11-15 Pei Dang , Hua Liu , Tao Qian

We derive two main results: First, assume that $A$, $B$, $A_n$, $B_n$ are self-adjoint operators in the Hilbert space $\mathcal{H}$, and suppose that $A_n$ converges to $A$ and $B_n$ to $B$ in strong resolvent sense as $n \to \infty$. Fix…

Spectral Theory · Mathematics 2016-02-03 Alan Carey , Fritz Gesztesy , Galina Levitina , Roger Nichols , Denis Potapov , Fedor Sukochev

Let $T$ be a bilinear Calder\'{o}n-Zygmund singular integral operator and $T_*$ be its corresponding truncated maximal operator. The commutators in the $i$-$th$ entry and the iterated commutators of $T_*$ are defined by $$…

Classical Analysis and ODEs · Mathematics 2013-12-16 Yong Ding , Ting Mei , Qingying Xue

Consider a finite dimensional complex Hilbert space $\cH$, with $dim(\cH) \geq 3$, define $\bS(\cH):= \{x\in \cH \:|\: ||x||=1\}$, and let $\nu_\cH$ be the unique regular Borel positive measure invariant under the action of the unitary…

Mathematical Physics · Physics 2017-08-23 Valter Moretti , Davide Pastorello

This article establishes a bilinear embedding for second-order divergence-form operators with complex coefficients, characterized by the simultaneous presence of first-order terms and negative potentials. This work provides a further…

Analysis of PDEs · Mathematics 2026-05-15 Lorenzo Luciano Morelato , Andrea Poggio

We consider divergence form elliptic operators $L=-\dv A(x)\nabla$, defined in $\mathbb{R}^{n+1}=\{(x,t)\in\mathbb{R}^{n}\times\mathbb{R}\}, n \geq 2$, where the $L^{\infty}$ coefficient matrix $A$ is $(n+1)\times(n+1)$, uniformly elliptic,…

Classical Analysis and ODEs · Mathematics 2007-05-23 S. Hofmann

The aim of this article is to introduce the H-infinity functional calculus for unbounded bisectorial operators in a Clifford module over the algebra R_n. While recent studies have focused on bounded operators or unbounded paravector…

Functional Analysis · Mathematics 2025-02-17 Francesco Mantovani , Peter Schlosser

The simplest and most natural examples of completely nonunitary contractions on separable complex Hilbert spaces which have polynomial characteristic functions are the nilpotent operators. The main purpose of this paper is to prove the…

Functional Analysis · Mathematics 2017-04-20 Ciprian Foias , Carl Pearcy , Jaydeb Sarkar

The so-called triangular Hilbert transform is an elegant trilinear singular integral form which specializes to many well studied objects of harmonic analysis. We investigate $L^p$ bounds for a dyadic model of this form in the particular…

Classical Analysis and ODEs · Mathematics 2016-03-16 Vjekoslav Kovač , Christoph Thiele , Pavel Zorin-Kranich

We consider the Hilbert-type operator defined by $$ H_{\omega}(f)(z)=\int_0^1 f(t)\left(\frac{1}{z}\int_0^z B^{\omega}_t(u)\,du\right)\,\omega(t)dt,$$ where $\{B^{\omega}_\zeta\}_{\zeta\in\mathbb{D}}$ are the reproducing kernels of the…

Complex Variables · Mathematics 2026-02-16 José Ángel Peláez , Elena de la Rosa