Abstract
Let C be a closed, convex and nonempty subset of a Banach space X. Let \({T : C \rightarrow X}\) be a nonexpansive inward mapping. We consider the boundary point map \({h_{C,T } : C \rightarrow \mathbb{R}}\) depending on C and T defined by \({h_{C,T} = {\rm max}\{\lambda \in [0,1] : [(1-\lambda)x + \lambda Tx] \in C\}}\), for all \({x \in C}\). Then for a suitable step-by-step construction of the control coefficients by using the function \({h_{C,T }}\), we show the convergence of the Mann-Dotson algorithm to a fixed point of T. We obtain strong convergence if \({\sum\limits_{n \in \mathbb{N}} \alpha_{n} < \infty}\) and weak convergence if \({\sum\limits_{n \in \mathbb{N}} \alpha_{n} = \infty}\).
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Acknowledgements
The authors thank the anonymous reviewers for for their valuable suggestions regarding the improvement of the paper. This paper is funded by Ministero dell’Istruzione, Universitá e Ricerca (MIUR) and Gruppo Nazionale di Analisi Matemarica e Probabilitá e Applicazioni (GNAMPA).
The first author declares that his contribution would not have been possible without the help of Maria Grazia Atzeri, Carla Mazzone and of the co-author Luigi Muglia.
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Marino, G., Muglia, L. Boundary Point Method and the Mann–Dotson Algorithm for Non-self Mappings in Banach Spaces. Milan J. Math. 87, 73–91 (2019). https://doi.org/10.1007/s00032-019-00293-4
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DOI: https://doi.org/10.1007/s00032-019-00293-4