Approximating fixed points of nonexpansive mappings in CAT(0) spaces

Let C be a nonempty closed convex subset of a complete CAT(0) space and T : C → C be a nonexpansive mapping with F(T) := {x ∈ C : Tx = x} ≠ ø. Suppose {xn} is generated iteratively by x1 ∈ C, xn+1 = tnT[snTxn (1 - sn)xn] (1 - tn)xn for all n ≥ 1, where {tn} and {sn} are real sequences in [0, 1] such...

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Bibliographic Details
Main Authors: Thanomsak Laokul, Bancha Panyanak
Format: Journal
Published: 2018
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Online Access:https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=77953330742&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/59721
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Institution: Chiang Mai University
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Summary:Let C be a nonempty closed convex subset of a complete CAT(0) space and T : C → C be a nonexpansive mapping with F(T) := {x ∈ C : Tx = x} ≠ ø. Suppose {xn} is generated iteratively by x1 ∈ C, xn+1 = tnT[snTxn (1 - sn)xn] (1 - tn)xn for all n ≥ 1, where {tn} and {sn} are real sequences in [0, 1] such that one of the following two conditions is satisfied : (i) tn ∈ [a, b] and sn ∈ [0, b] for some a, b with 0 < a < b < 1 , (ii) tn ∈ [a, 1] and sn ∈ [a, b] for some a, b with 0 < a ≤ b < 1. Then the sequence {xn} δ-converges to a fixed point of T. This is an analog of a result on weak convergence theorem in Banach spaces of Takahashi and Kim [W. Takahashi and G. E. Kim, Approximating fixed points of nonexpansive mappings in Banach spaces, Math. Japonica. 48 no. 1 (1998), 1-9]. Strong convergence of the iterative sequence {xn} is also discussed.