A strongly convergent Krasnosel’skiǐ–Mann-type algorithm for finding a common fixed point of a countably infinite family of nonexpansive operators in Hilbert spaces

Autor: Dennis Meier, Radu Ioan Bot
Rok vydání: 2021
Předmět:
Zdroj: Journal of Computational and Applied Mathematics. 395:113589
ISSN: 0377-0427
DOI: 10.1016/j.cam.2021.113589
Popis: In this article, we propose a Krasnosel’skiǐ–Mann-type algorithm for finding a common fixed point of a countably infinite family of nonexpansive operators ( T n ) n ≥ 0 in Hilbert spaces. We formulate an asymptotic property which the family ( T n ) n ≥ 0 has to fulfill such that the sequence generated by the algorithm converges strongly to the element in ⋂ n ≥ 0 Fix T n with minimum norm. Based on this, we derive a forward–backward algorithm that allows variable step sizes and generates a sequence of iterates that converge strongly to the zero with minimum norm of the sum of a maximally monotone operator and a cocoercive one. We demonstrate the superiority of the forward–backward algorithm with variable step sizes over the one with constant step size by means of numerical experiments on variational image reconstruction and split feasibility problems in infinite dimensional Hilbert spaces.
Databáze: OpenAIRE