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The correspondence between the monotonicity of a (possibly) set-valued operator and the firm nonexpansiveness of its resolvent is a key ingredient in the convergence analysis of many optimization algorithms. Firmly nonexpansive operators…

Optimization and Control · Mathematics 2019-02-27 Heinz H. Bauschke , Walaa M. Moursi , Xianfu Wang

We introduce regularity notions for averaged nonexpansive operators. Combined with regularity notions of their fixed point sets, we obtain linear and strong convergence results for quasicyclic, cyclic, and random iterations. New convergence…

Optimization and Control · Mathematics 2014-02-25 Heinz H. Bauschke , Dominikus Noll , Hung M. Phan

We introduce certain linear positive operators and study some approximation properties of these operators in the space of functions, continuous on a compact set, of two variables. We also find the order of this approximation by using…

Classical Analysis and ODEs · Mathematics 2007-09-24 Fatma Tasdelen , Ali Olgun , Gulen Bascanbaz-Tunca

Nonexpansive mappings play a central role in modern optimization and monotone operator theory because their fixed points can describe solutions to optimization or critical point problems. It is known that when the mappings are sufficiently…

Functional Analysis · Mathematics 2020-04-28 Salihah Alwadani , Heinz H. Bauschke , Xianfu Wang

We in this paper study the nonexpansive operators equipped with arbitrary metric and investigate the connections between firm nonexpansiveness, cocoerciveness and averagedness. The convergence of the associated fixed-point iterations is…

Optimization and Control · Mathematics 2022-10-11 Feng Xue

Boundedness for a class of projection operators, which includes the coordinate projections, on matrix weighted $L^p$-spaces is completely characterised in terms of simple scalar conditions. Using the projection result, sufficient…

Functional Analysis · Mathematics 2015-03-09 Morten Nielsen , Morten Grud Rasmussen

Because of Minty's classical correspondence between firmly nonexpansive mappings and maximally monotone operators, the notion of a firmly nonexpansive mapping has proven to be of basic importance in fixed point theory, monotone operator…

Functional Analysis · Mathematics 2011-12-22 Heinz H. Bauschke , Victoria Martin-Marquez , Sarah M. Moffat , Xianfu Wang

The aim of this work is to introduced the concept of the best one-sided approximation of unbounded functions in weighted space by using algebraic operators in terms the average modulus of smoothness. We also show an estimate of the degree…

General Mathematics · Mathematics 2023-12-15 Raheam A. Al-Saphory , Abdullah A. Al-Hayani , Alaa A. Auad

In this paper we characterize $m$-isometric and quasi-$m$-isometric weighted composition operators on the Hilbert space $L^2(\mu)$. Also, we find that normal-$m$-isometry and normal quasi-$m$-isometry weighted composition operators have…

Functional Analysis · Mathematics 2025-09-25 M. S. Al Ghafri , Y. Estaremi , M. Z. Gashti

Recent work by several authors has revealed the existence of many unexpected classes of normal weighted composition operators. On the other hand, it is known that every normal operator is a complex symmetric operator. We therefore undertake…

Functional Analysis · Mathematics 2012-05-22 Stephan Ramon Garcia , Christopher Hammond

In this paper, we study the basic properties such as boundedness and compactness of composition operators on discrete analogue of generalized Hardy space defined on a homogeneous rooted tree. Also, we compute the operator norm of…

Functional Analysis · Mathematics 2016-10-03 Perumal Muthukumar , Saminathan Ponnusamy

We introduce the resolvent composition, a monotonicity-preserving operation between a linear operator and a set-valued operator, as well as the proximal composition, a convexity-preserving operation between a linear operator and a function.…

Optimization and Control · Mathematics 2023-07-25 Patrick L. Combettes

In this paper, we investigate the behavior of the bounds of the composition for rough singular integral operators on the weighted space. More precisely, we obtain the quantitative weighted bounds of the composite operator for two singular…

Classical Analysis and ODEs · Mathematics 2019-12-20 Guoen Hu , Xudong Lai , Qingying Xue

In this paper, we study weighted composition operators on the Fock space. We show that a weighted composition operator is cohyponorma if and only if it is normal. Moreover, we give a complete characterization of closed range weighted…

Functional Analysis · Mathematics 2018-09-14 Mahsa Fatehi

Many iterative optimization algorithms involve compositions of special cases of Lipschitz continuous operators, namely firmly nonexpansive, averaged and nonexpansive operators. The structure and properties of the compositions are of…

Optimization and Control · Mathematics 2020-01-01 Pontus Giselsson , Walaa M. Moursi

Compositional generalization, the ability to recognize familiar parts in novel contexts, is a defining property of intelligent systems. Although modern models are trained on massive datasets, they still cover only a tiny fraction of the…

Computer Vision and Pattern Recognition · Computer Science 2026-03-02 Arnas Uselis , Andrea Dittadi , Seong Joon Oh

Bounded composition operators in Paley-Wiener spaces have simple forms, and they are just operators composed through affine mappings of the complex plane. The purpose of this article is to explore some notions about bounded operators and…

Functional Analysis · Mathematics 2025-11-24 Carlos F. Álvarez , O. R. Severiano

Maximally monotone operators and firmly nonexpansive mappings play key roles in modern optimization and nonlinear analysis. Five years ago, it was shown that if finitely many firmly nonexpansive operators are all asymptotically regular…

Optimization and Control · Mathematics 2017-12-05 Heinz H. Bauschke , Walaa M. Moursi

We study which standard operators of probabilistic process calculi allow for compositional reasoning with respect to bisimulation metric semantics. We argue that uniform continuity (generalizing the earlier proposed property of…

Logic in Computer Science · Computer Science 2019-03-14 Daniel Gebler , Kim G. Larsen , Simone Tini

This article is concerned with a geometric tool given by a pair of projector operators defined by almost product structures on finite dimensional manifolds, polarized by a distribution of constant rank and also endowed with some geometric…

Mathematical Physics · Physics 2011-10-11 Paulo Pitanga , Paulo R. Rodrigues