Maximum Modulus Principle For Multipliers and Mean Ergodic Multiplication Operators

Spectra and ergodic properties of multiplication and convolution operators on the space $\mathcal{S}(\mathbb{R})$

In this paper we investigate the spectra and the ergodic properties of the multiplication operators and the convolution operators acting on the Schwartz space $\mathcal{S}(\mathbb{R})$ of rapidly decreasing functions, i.e., operators of the form $M_h: \mathcal{S}(\mathbb{R})\to\mathcal{S}(\mathbb{R})$, $f \mapsto h f $, and $C_T\colon \mathcal{S}(\mathbb{R})\to\mathcal{S}(\mathbb{R})$, $f\mapsto T\star f$. Precisely, we determine their spectra and characterize when those operators are power bounded and mean ergodic.

Mean Ergodicity of Multiplication Operators on the Bloch and Besov Spaces

In this paper, the power boundedness and mean ergodicity of multiplication operators are investigated on the Bloch space B, the little Bloch space B0 and the Besov Space Bp. We completely characterize power bounded, mean ergodic and uniformly mean ergodic multiplication operators on B and B0.

加权 Dirichlet 空间中乘法算子的均值遍历性

Mean ergodicity of multiplication operators in weighted Dirichlet spaces

本文刻画了加权 Dirichlet 空间中乘法算子及其伴随算子的有界性条件，证明了均值遍历性与 Cesàro 有界性的等价性，并构造出一致均值遍历但非幂有界的算子特例。

Isometries and spectra of multiplication operators on the Bloch space

In this paper, we establish bounds on the norm of multiplication operators on the Bloch space of the unit disk via weighted composition operators. In doing so, we characterize the isometric multiplication operators to be precisely those induced by constant functions of modulus 1. We then describe the spectrum of the multiplication operators in terms of the range of the symbol. Lastly, we identify the isometries and spectra of a particular class of weighted composition operators on the Bloch space.

Multiplication operators on the Bloch space of bounded homogeneous domains

In this paper, we study the multiplication operators on the Bloch space of a bounded homogeneous domain in $\mathbb{C}^n$. Specifically, we characterize the bounded and the compact multiplication operators, establish estimates on the operator norm, and determine the spectrum. We prove that the only bounded multiplication operators on the Bloch space of the polydisk are those whose symbol is constant. Furthermore, we prove that for a large class of bounded symmetric domains, the isometric multiplication operators are those whose symbol is a constant of modulus one.

On Nörlund summation and Ergodic Theory, with applications to power series of Hilbert contractions

We show that if ${\bf a}=(a_n)_{n\in \N}$ is a good weight for the dominated weighted ergodic theorem in $L^p$, $p>1$, then the Nörlund matrix $N_{\bf a}=\{a_{i-j}/A_i\}_{0\le j\le i}$, $A_i=\sum_{k=0}^i |a_k|$ is bounded on $\ell^p(\N)$. We study the regularity (convergence in norm, almost everywhere) of operators in ergodic theory: power series of Hilbert contractions, and power series $\sum_{n\in \N} a_nP_nf $ of $L^2$-contractions, and establish similar tight relations with the Nörlund operator associated to the modulus coefficient sequence $(|a_n|)_{n\in \N}$.