Mean ergodic theorems for a sequence of nonexpansive mappings in complete CAT(0) spaces and its applications

In this article, we prove ergodic convergence for a sequence of nonexpansive mappings in Hadamard (complete CAT(0){\rm{CAT}}\left(0)) spaces. Our result extends the nonlinear ergodic theorem by Baillon for nonexpansive mappings from Hilbert spaces to Hadamard spaces. We further establish the standar...

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Main Authors: Termkaew Sakan, Chaipunya Parin, Kohsaka Fumiaki
Format: Article
Language:English
Published: De Gruyter 2023-10-01
Series:Open Mathematics
Subjects:
Online Access:https://doi.org/10.1515/math-2023-0121
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author Termkaew Sakan
Chaipunya Parin
Kohsaka Fumiaki
author_facet Termkaew Sakan
Chaipunya Parin
Kohsaka Fumiaki
author_sort Termkaew Sakan
collection DOAJ
description In this article, we prove ergodic convergence for a sequence of nonexpansive mappings in Hadamard (complete CAT(0){\rm{CAT}}\left(0)) spaces. Our result extends the nonlinear ergodic theorem by Baillon for nonexpansive mappings from Hilbert spaces to Hadamard spaces. We further establish the standard nonlinear ergodic theorem and apply our results to the problem of finding a common fixed point of a countable family of nonexpansive mappings. Finally, we propose some applications of our results to solve convex optimization problems in Hadamard spaces.
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spelling doaj.art-93ad94dc39ab4aac851b7e3c8bce66002023-10-12T14:06:59ZengDe GruyterOpen Mathematics2391-54552023-10-01211708210.1515/math-2023-0121Mean ergodic theorems for a sequence of nonexpansive mappings in complete CAT(0) spaces and its applicationsTermkaew Sakan0Chaipunya Parin1Kohsaka Fumiaki2Department of Mathematics, Faculty of Science, King Mongkut’s University of Technology Thonburi, 126 Pracha Uthit Rd., Bang Mod, Thung Khru, Bangkok, 10140, ThailandDepartment of Mathematics, Faculty of Science, King Mongkut’s University of Technology Thonburi, 126 Pracha Uthit Rd., Bang Mod, Thung Khru, Bangkok, 10140, ThailandDepartment of Mathematical Sciences, Faculty of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa, 259-1292, JapanIn this article, we prove ergodic convergence for a sequence of nonexpansive mappings in Hadamard (complete CAT(0){\rm{CAT}}\left(0)) spaces. Our result extends the nonlinear ergodic theorem by Baillon for nonexpansive mappings from Hilbert spaces to Hadamard spaces. We further establish the standard nonlinear ergodic theorem and apply our results to the problem of finding a common fixed point of a countable family of nonexpansive mappings. Finally, we propose some applications of our results to solve convex optimization problems in Hadamard spaces.https://doi.org/10.1515/math-2023-0121convex optimizationergodic theoremfixed pointhadamard spacenonexpansive mapping47h0947h1047h2547n10
spellingShingle Termkaew Sakan
Chaipunya Parin
Kohsaka Fumiaki
Mean ergodic theorems for a sequence of nonexpansive mappings in complete CAT(0) spaces and its applications
Open Mathematics
convex optimization
ergodic theorem
fixed point
hadamard space
nonexpansive mapping
47h09
47h10
47h25
47n10
title Mean ergodic theorems for a sequence of nonexpansive mappings in complete CAT(0) spaces and its applications
title_full Mean ergodic theorems for a sequence of nonexpansive mappings in complete CAT(0) spaces and its applications
title_fullStr Mean ergodic theorems for a sequence of nonexpansive mappings in complete CAT(0) spaces and its applications
title_full_unstemmed Mean ergodic theorems for a sequence of nonexpansive mappings in complete CAT(0) spaces and its applications
title_short Mean ergodic theorems for a sequence of nonexpansive mappings in complete CAT(0) spaces and its applications
title_sort mean ergodic theorems for a sequence of nonexpansive mappings in complete cat 0 spaces and its applications
topic convex optimization
ergodic theorem
fixed point
hadamard space
nonexpansive mapping
47h09
47h10
47h25
47n10
url https://doi.org/10.1515/math-2023-0121
work_keys_str_mv AT termkaewsakan meanergodictheoremsforasequenceofnonexpansivemappingsincompletecat0spacesanditsapplications
AT chaipunyaparin meanergodictheoremsforasequenceofnonexpansivemappingsincompletecat0spacesanditsapplications
AT kohsakafumiaki meanergodictheoremsforasequenceofnonexpansivemappingsincompletecat0spacesanditsapplications