Approximating xed points of generalized non-expansive non-self mappings in CAT(0) spaces

محورهای موضوعی : Applied Mathematics

Saeed Saeed Shabani ¹ ( Department of Mathematics, Izeh Branch, Islamic Azad University, Izeh, Iran. )
S.J. Hoseini Ghoncheh ² ( Department of Mathematics, Takestan Branch, Islamic Azad University, Takestan, Iran. )

تاریخ دریافت : 1394/07/08 تاریخ پذیرش : 1394/07/08 تاریخ انتشار : 1392/02/11

کلید واژه: fixed point, CAT(0) spaces, generalized non-expansive non-self mappings,

چکیده مقاله :

Suppose K is a nonempty closed convex subset of a complete CAT(0) spaceX with the nearest point projection P from X onto K. Let T : K →X be anonself mapping, satisfying condition (C) with F(T) :={ x εK : Tx = x}≠Φ.Suppose fxng is generated iteratively by x1εK, xn+1 = P((1-αn)xn+αnTP[(1-αn)xn+βnTxn]),n≥1, where {αn}and {βn} are real sequences in[ε,1-ε] for some  ε in(0,1). Then {xn} is Δ-
􀀀convergence to some point x* inF(T). This work extends a result of Laowang and Panyanak [5] to the case ofgeneralized nonexpansive nonself mappings.

چکیده انگلیسی:

Suppose K is a nonempty closed convex subset of a complete CAT(0) spaceX with the nearest point projection P from X onto K. Let T : K → X be anonself mapping, satisfying condition (C) with F(T) :={ x ε K : Tx = x}≠Φ.Suppose fxng is generated iteratively by x1ε K, xn+1 = P((1-αn)xn+αnTP[(1-αn)xn+βnTxn]),n≥1, where {αn }and {βn } are real sequences in[ε,1-ε] for some  ε in (0,1). Then {xn} is Δ-
􀀀convergence to some point x* inF(T). This work extends a result of Laowang and Panyanak [5] to the case ofgeneralized nonexpansive nonself mappings.

منابع و مأخذ:

[1] M. Bridson and A. Hae iger, Metric Spaces of Non-Positive Curvature, vol. 319
of Fundamental Principles of Mathematical Sciences, Berlin, Germany, 1999.
[2] S. Dhompongsa and W. Kirk and B. Sims, xed point of uniformly lipschitzian
mappings, Nonlinear Anal. 65 (2006), 762{772.
[3] S. Dhompongsa and B. Panyanak, On
-convergence theorems in CAT(0)
spaces. Computers and Mathematics with Applications. 56 (2008), 2572{2579.
[4] W. Kirk and B. Panyanak, A concept of convergence in geodesic spaces. Nonlinear
Anal. 68 (2008), 3689{3696.
[5] W. Laowang and B. Panyanak, Approximating xed points of nonexpansive non-
self mappings in CAT(0) spaces. Fixed Point Theory Appl. Article ID 367274
(2010), 11 pages.
[6] T. Suzuki, Fixed point theorems and convergence theorems for some generalized
nonexpansive mapping, Math. Anal. Appl. 340 (2008), 1088{1095.
[7] A. Razani and H. Salahifard, Invariant approximation for CAT(0) spaces, Non-
linear Anal. 72 (2010), 2421{2425.
[8] S. Dhompongsa, W. A. Kirk and B. Panyanak, Nonexpansive set-valued mappings
in metric and Banach spaces, J. Nonlinear and Convex Anal. 8 (2007), 35-45.