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In this paper we characterize for 0 < p \leq \infty, the closed subspaces of Hp that are invariant under multiplication by all powers of a finite Blaschke factor B, except the first power. Our result clearly generalizes the invariant…

Functional Analysis · Mathematics 2012-08-01 Niteesh Sahni , Dinesh Singh

The fermion doubling theorem plays a pivotal role in Hermitian topological materials. It states, for example, that Weyl points must come in pairs in three-dimensional semimetals. Here, we present an extension of the doubling theorem to…

Mesoscale and Nanoscale Physics · Physics 2021-03-03 Zhesen Yang , A. P. Schnyder , Jiangping Hu , Ching-Kai Chiu

In this paper author was proved the boundedness of the multidimensional Hardy type operator in weighted Lebesgue spaces with a variable exponent. As an application we prove the boundedness of certain sublinear operators on the weighted…

Classical Analysis and ODEs · Mathematics 2013-03-05 Rovshan A. Bandaliev

A closed subspace is invariant under the Ces\`aro operator $\mathcal{C}$ on the classical Hardy space $H^2(\mathbb D)$ if and only if its orthogonal complement is invariant under the $C_0$-semigroup of composition operators induced by the…

Functional Analysis · Mathematics 2022-09-27 Eva A. Gallardo-Gutiérrez , Jonathan R. Partington

This paper considers two commuting smooth transformations on a Banach space, and proves the sub-additivity of the measure theoretic entropies under mild conditions. Furthermore, some additional conditions are given for the equality of the…

Dynamical Systems · Mathematics 2025-07-31 ChiYi Luo , Yun Zhao

We prove two new equivalences of the Feichtinger conjecture that involve reproducing kernel Hilbert spaces. We prove that if for every Hilbert space, contractively contained in the Hardy space, each Bessel sequence of normalized kernel…

Functional Analysis · Mathematics 2010-12-07 Sneh Lata , Vern I. Paulsen

Recent work in Dynamical Sampling has been centered on characterizing frames obtained by the orbit of a vector under a bounded operator. We prove a necessary and sufficient condition for a pair of bounded commuting operators on a separable…

Functional Analysis · Mathematics 2025-07-10 Victor Bailey , Carlos Cabrelli

We prove the Invariant Subspace Conjecture for separable Hilbert spaces.

Functional Analysis · Mathematics 2023-07-24 Charles W. Neville

A particular case of [07] was generalized from contractions to polynomially bounded operators in [G19]. Namely, it is proved in [G19] that if the unitary asymptote of a polynomially bounded operator $T$ contains the bilateral shift of…

Functional Analysis · Mathematics 2022-12-06 Maria F. Gamal'

In this article, we completely classify invariant subspaces of finite-rank perturbations of a class of Toeplitz operators on vector-valued Hardy spaces. As a consequence, in the vector-valued setting, we characterize invariant and almost…

Functional Analysis · Mathematics 2026-02-25 Arshad Khan , Sneh Lata , Dinesh Singh

In 2015, Yanni Chen, Don Hadwin and Junhao Shen proved a noncommutative version of Beurling's theorems for a continuous unitarily invariant norm $% \alpha $ on a tracial von Neumann algebra $\left( \mathcal{M},\tau \right) $ where $\alpha $…

Operator Algebras · Mathematics 2018-01-17 Haihui Fan , Don Hadwin , Wenjing Liu

Following upon results of Putinar, Sun, Wang, Zheng and the first author, we provide models for the restrictions of the multiplication by a finite Balschke product on the Bergman space in the unit disc to its reducing subspaces. The models…

Functional Analysis · Mathematics 2014-09-16 Ronald G. Douglas , Dinesh Kumar Keshari , Anjian Xu

We relate dual-band general Toeplitz operators to block truncated Toeplitz operators and, via equivalence after extension, with Toeplitz operators with $4 \times 4$ matrix symbols. We discuss their norm, their kernel, Fredhomlness,…

Functional Analysis · Mathematics 2021-06-04 M. Cristina Câmara , Ryan O'Loughlin , Jonathan R. Partington

We extend to multilinear Hankel operators the fact that truncation of bounded Hankel operators is bounded. We prove and use a continuity property of a kind of bilinear Hilbert transforms on product of Lipschitz spaces and Hardy spaces.

Functional Analysis · Mathematics 2007-05-23 Sandrine Grellier , Mohammad Kacim

A Helson-Lowdenslager type result has been proved by Chen in the context of Lebesgue spaces of the unit circle equipped with a continuous rotationally symmetric norm by studying the simply invariant subspaces of the operator of…

Functional Analysis · Mathematics 2023-04-03 Apoorva Singh , Niteesh Sahni

In this article we study invariance properties of shift-invariant spaces in higher dimensions. We state and prove several necessary and sufficient conditions for a shift-invariant space to be invariant under a given closed subgroup of…

Classical Analysis and ODEs · Mathematics 2010-02-08 Magalí Anastasio , Carlos Cabrelli , Victoria Paternostro

We shed new light on Heisenberg's uncertainty principle in the sense of Beurling, by offering an essentially different proof which permits us to weaken the assumptions substantially, and examples show that the result is sharp. The proof…

Functional Analysis · Mathematics 2013-11-11 Haakan Hedenmalm

We prove a sufficient condition for frame-type wavelet series in $L^p$, the Hardy space $H^1$, and BMO. For example, functions in these spaces are shown to have expansions in terms of the Mexican hat wavelet, thus giving a strong answer to…

Classical Analysis and ODEs · Mathematics 2012-06-13 H. -Q. Bui , R. S. Laugesen

This paper is devoted to a study of the multiple recurrence of two commuting transformations. We derive a result which is similar but not identical to that of one single transformation established by Bergelson, Host and Kra. We will use the…

Dynamical Systems · Mathematics 2009-12-18 Qing Chu

We give a simple proof of the Kernel theorem for the space of tempered ultradistributions of Beurling - Komatsu type, using the characterization of Fourier-Hermite coefficients of the elements of the space. We prove in details that the test…

Functional Analysis · Mathematics 2007-05-23 Z. Lozanov-Crvenkovic , D. Perisic