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Firmly nonexpansive operators arise naturally as resolvents of monotone operators and as generalizations of projections and proximal mappings in convex optimization and fixed point theory. While their iterates are known to converge weakly…

Optimization and Control · Mathematics 2026-05-26 Heinz H. Bauschke , Tran Thanh Tung

We consider linear operators defined on a subspace of a complex Banach space into its topological antidual acting positively in a natural sense. The goal of this paper is to investigate of this kind of operators. The main theorem is a…

Functional Analysis · Mathematics 2014-09-12 Zoltán Sebestyén , Zsolt Szűcs , Zsigmond Tarcsay

This paper proposes a data-driven approach for constructing firmly nonexpansive operators. We demonstrate its applicability in Plug-and-Play (PnP) methods, where classical algorithms such as Forward-Backward splitting, Chambolle-Pock…

Optimization and Control · Mathematics 2025-10-29 Kristian Bredies , Jonathan Chirinos-Rodriguez , Emanuele Naldi

Resolvent compositions were recently introduced as monotonicity-preserving operations that combine a set-valued monotone operator and a bounded linear operator. They generalize in particular the notion of a resolvent average. We analyze the…

Functional Analysis · Mathematics 2026-01-30 Diego J. Cornejo

We prove weak and strong convergence theorems for a double Krasnoselskij type iterative method to approximate coupled solutions of a bivariate nonexpansive operator F : C x C --> C, where C is a nonempty closed and convex subset of a…

Functional Analysis · Mathematics 2014-02-21 V. Berinde , A. R. Khan , M. Pacurar

In this note we will present an extension of the Krein-Rutman theorem for an abstract nonlinear, compact, positively 1-homogeneous, monotone non-decreasing operators on a Banach space and apply the result to many nonlinear elliptic partial…

Functional Analysis · Mathematics 2007-05-23 Rajesh Mahadevan

We propose a method for solving constrained fixed point problems involving compositions of Lipschitz pseudo contractive and firmly nonexpansive operators in Hilbert spaces. Each iteration of the method uses separate evaluations of these…

Optimization and Control · Mathematics 2011-01-10 Luis M. Briceño-Arias

The aim of this survey is to present the main important techniques and tools from variational analysis used for first and second order dynamical systems of implicit type for solving monotone inclusions and non-smooth optimization problems.…

Optimization and Control · Mathematics 2020-07-02 Ernö Robert Csetnek

Properties of compositions and convex combinations of averaged nonexpansive operators are investigated and applied to the design of new fixed point algorithms in Hilbert spaces. An extended version of the forward-backward splitting…

Functional Analysis · Mathematics 2014-10-09 Patrick L. Combettes , Isao Yamada

The correspondence between the class of nonexpansive mappings and the class of maximally monotone operators via the reflected resolvents of the latter has played an instrumental role in the convergence analysis of the splitting methods.…

Optimization and Control · Mathematics 2022-05-19 Leon Liu , Walaa M. Moursi , Jon Vanderwerff

While monotone operator theory is often studied on Hilbert spaces, many interesting problems in machine learning and optimization arise naturally in finite-dimensional vector spaces endowed with non-Euclidean norms, such as…

Optimization and Control · Mathematics 2025-08-26 Alexander Davydov , Saber Jafarpour , Anton V. Proskurnikov , Francesco Bullo

We study monotone extension problems in the general framework of dual systems, without assuming separation. The paper develops a compact target-set formulation that includes multivalued operators as a special case and allows the initial set…

Functional Analysis · Mathematics 2026-05-28 M. D. Voisei

We introduce the class of $\alpha$-firmly nonexpansive and quasi $\alpha$-firmly nonexpansive operators on $r$-uniformly convex Banach spaces. This extends the existing notion from Hilbert spaces, where $\alpha$-firmly nonexpansive…

Functional Analysis · Mathematics 2025-03-11 Arian Bërdëllima , Gabriele Steidl

In two recent papers we introduced some new techniques for constructing an extension of a probability-preserving system $T:\mathbb{Z}^d\curvearrowright (X,\mu)$ that enjoys certain desirable properties in connexion with the asymptotic…

Dynamical Systems · Mathematics 2014-09-09 Tim Austin

We study the existence and uniqueness of (locally) absolutely continuous trajectories of a dynamical system governed by a nonexpansive operator. The weak convergence of the orbits to a fixed point of the operator is investigated by relying…

Dynamical Systems · Mathematics 2014-12-16 Radu Ioan Bot , Ernö Robert Csetnek

We adopt an operator-theoretic perspective to analyze a class of nonlinear fixed-point iterations and discrete-time dynamical systems. Specifically, we study the Krasnoselskij iteration - at the heart of countless algorithmic schemes and…

Systems and Control · Electrical Eng. & Systems 2025-06-24 Diego Deplano , Sergio Grammatico , Mauro Franceschelli

We present a generalization of the proximal operator defined through a convex combination of convex objectives, where the coefficients are updated in a minimax fashion. We prove that this new operator is Bregman firmly nonexpansive with…

Optimization and Control · Mathematics 2025-04-14 Mastane Achab

This paper provides a fixed point theorem for asymptotically nonexpansive mappings in uniformly convex hyperbolic spaces as well as new effective results on the Krasnoselski-Mann iterations of such mappings. The latter were found using…

Functional Analysis · Mathematics 2008-03-26 Ulrich Kohlenbach , Laurentiu Leustean

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

In this paper, we first introduce an iterative process in modular function spaces and then extend the idea of a {\lambda}-firmly nonexpansive mapping from Banach spaces to modular function spaces. We call such mappings as…

Functional Analysis · Mathematics 2021-11-23 Safeer Hussain Khan