Iterative methods for monotone nonexpansive mappings in uniformly convex spaces

We show the nonlinear ergodic theorem for monotone 1-Lipschitz mappings in uniformly convex spaces: if C is a bounded closed convex subset of an ordered uniformly convex space (X, ∣·∣, ⪯), T:C → C a monotone 1-Lipschitz mapping and x ⪯ T(x), then the sequence of averages 1n∑i=0n−1Ti(x)$ \frac{1}{n}\...

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Main Authors: Shukla Rahul, Wiśnicki Andrzej
Format: Article
Language:English
Published: De Gruyter 2021-03-01
Series:Advances in Nonlinear Analysis
Subjects:
Online Access:https://doi.org/10.1515/anona-2020-0170
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author Shukla Rahul
Wiśnicki Andrzej
author_facet Shukla Rahul
Wiśnicki Andrzej
author_sort Shukla Rahul
collection DOAJ
description We show the nonlinear ergodic theorem for monotone 1-Lipschitz mappings in uniformly convex spaces: if C is a bounded closed convex subset of an ordered uniformly convex space (X, ∣·∣, ⪯), T:C → C a monotone 1-Lipschitz mapping and x ⪯ T(x), then the sequence of averages 1n∑i=0n−1Ti(x)$ \frac{1}{n}\sum\nolimits_{i=0}^{n-1}T^{i}(x) $ converges weakly to a fixed point of T. As a consequence, it is shown that the sequence of Picard’s iteration {Tn(x)} also converges weakly to a fixed point of T. The results are new even in a Hilbert space. The Krasnosel’skiĭ-Mann and the Halpern iteration schemes are studied as well.
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spelling doaj.art-5020926b1755482e8b2568d35f75cf1b2022-12-21T18:36:01ZengDe GruyterAdvances in Nonlinear Analysis2191-94962191-950X2021-03-011011061107010.1515/anona-2020-0170Iterative methods for monotone nonexpansive mappings in uniformly convex spacesShukla Rahul0Wiśnicki Andrzej1Department of Mathematics & Applied Mathematics, University of Johannesburg, Kingsway Campus, Auckland Park 2006, South AfricaDepartment of Mathematics, Pedagogical University of Krakow, PL-30-084Cracow, PolandWe show the nonlinear ergodic theorem for monotone 1-Lipschitz mappings in uniformly convex spaces: if C is a bounded closed convex subset of an ordered uniformly convex space (X, ∣·∣, ⪯), T:C → C a monotone 1-Lipschitz mapping and x ⪯ T(x), then the sequence of averages 1n∑i=0n−1Ti(x)$ \frac{1}{n}\sum\nolimits_{i=0}^{n-1}T^{i}(x) $ converges weakly to a fixed point of T. As a consequence, it is shown that the sequence of Picard’s iteration {Tn(x)} also converges weakly to a fixed point of T. The results are new even in a Hilbert space. The Krasnosel’skiĭ-Mann and the Halpern iteration schemes are studied as well.https://doi.org/10.1515/anona-2020-0170monotone mappingnonexpansive mappingfixed pointergodic theorempicard iterationordered banach space47j2646b2047h0754f05
spellingShingle Shukla Rahul
Wiśnicki Andrzej
Iterative methods for monotone nonexpansive mappings in uniformly convex spaces
Advances in Nonlinear Analysis
monotone mapping
nonexpansive mapping
fixed point
ergodic theorem
picard iteration
ordered banach space
47j26
46b20
47h07
54f05
title Iterative methods for monotone nonexpansive mappings in uniformly convex spaces
title_full Iterative methods for monotone nonexpansive mappings in uniformly convex spaces
title_fullStr Iterative methods for monotone nonexpansive mappings in uniformly convex spaces
title_full_unstemmed Iterative methods for monotone nonexpansive mappings in uniformly convex spaces
title_short Iterative methods for monotone nonexpansive mappings in uniformly convex spaces
title_sort iterative methods for monotone nonexpansive mappings in uniformly convex spaces
topic monotone mapping
nonexpansive mapping
fixed point
ergodic theorem
picard iteration
ordered banach space
47j26
46b20
47h07
54f05
url https://doi.org/10.1515/anona-2020-0170
work_keys_str_mv AT shuklarahul iterativemethodsformonotonenonexpansivemappingsinuniformlyconvexspaces
AT wisnickiandrzej iterativemethodsformonotonenonexpansivemappingsinuniformlyconvexspaces