MODIFIED KRASNOSELSKI-MANN ITERATIONS FOR NONEXPANSIVE MAPPINGS IN HILBERT SPACES

  • Naidu, S.V.R. (Department of Applied Mathematics, Andhra University) ;
  • Sangago, Mengistu-Goa (Department of Applied Mathematics, Andhra University)
  • Received : 2009.09.23
  • Accepted : 2010.01.16
  • Published : 2010.05.30

Abstract

Let K be a nonempty closed convex subset of a real Hilbert space H. Let T : K $\rightarrow$ K be a nonexpansive mapping with a nonempty fixed point set Fix(T). Let f : K $\rightarrow$ K be a contraction mapping. Let {$\alpha_n$} and {$\beta_n$} be sequences in (0, 1) such that $\lim_{x{\rightarrow}0}{\alpha}_n=0$, (0.1) $\sum_{n=0}^{\infty}\;{\alpha}_n=+{\infty}$, (0.2) 0 < a ${\leq}\;{\beta}_n\;{\leq}$ b < 1 for all $n\;{\geq}\;0$. (0.3) Then it is proved that the modified Krasnoselski-Mann iterative sequence {$x_n$} given by {$x_0\;{\in}\;K$, $y_n\;=\;{\alpha}_{n}f(x_n)+(1-\alpha_n)x_n$, $n\;{\geq}\;0$, $x_{n+1}=(1-{\beta}_n)y_n+{\beta}_nTy_n$, $n\;{\geq}\;0$, (0.4) converges strongly to a point p $\in$ Fix(T} which satisfies the variational inequality

$\leq$ 0, z $\in$ Fix(T). (0.5) This result improves and extends the corresponding results of Yao et al[Y.Yao, H. Zhou, Y. C. Liou, Strong convergence of a modified Krasnoselski-Mann iterative algorithm for non-expansive mappings, J Appl Math Com-put (2009)29:383-389.

Keywords

References

  1. F. E. Browder, Semicontractive and semiaccretive nonlinear mappings in Banach spaces Bull. Amer. Math. Soc.74(1968), 660-665. https://doi.org/10.1090/S0002-9904-1968-11983-4
  2. C. Byrne, A unified treatment of some iterative algorithms in signal processing and image reconstruction, Inverse Problems 20 (2004) 103120.
  3. S. S. Chang, On Chidume's open questions and approximate solutions of multivalved strongly accretive mapping equations in Banach spaces, J. Math. Anal. Appl. 216(1997) 94-111. https://doi.org/10.1006/jmaa.1997.5661
  4. J. Diestel, Geometry of Banach Spaces - Selected Topics, (Lecture Notes in Mathematics; 485), Springer-Verlag Berlin. Heidelberg. New York 1975.
  5. M. A. Khamsi, W. A. Kirk, An Introuction to Metric Spaces and Fixed Point Theory, John Wiley & Sons, Inc. New York/ Chichester/ Weinheim/ Brisbane/ Sigapore/ Toronto, 2001.
  6. W. R. Mann, Mean value methods in iteration, Proc. Amer. Math. Soc. 4(1953)506-510 https://doi.org/10.1090/S0002-9939-1953-0054846-3
  7. Z. Opial, Weak convergence of the sequence of successive approximations for nonexpansive mappings Bull. Amer, Math. Soc. 73(1967),591-597. https://doi.org/10.1090/S0002-9904-1967-11761-0
  8. H. K. Xu, Iterative algorithms for nonlinear operators, J. London Math. Soc. 2(2002) 240-256.
  9. H. K. Xu, An Iterative Approach to Quadratic Optimization, J. Opt. Theory Appl. 116(2003) 659-678. https://doi.org/10.1023/A:1023073621589
  10. H. K. Xu, Viscosity approximation methods for nonexpansive mappings, J. Math. Anal. Appl. 298(2004) 279-291. https://doi.org/10.1016/j.jmaa.2004.04.059
  11. Y. Yao, H. Zhou, Y. C. Liou,Strong convergence of a modified Krasnoselski-Mann iterative algorithm for non-expansive mappings, J Appl Math Comput (2009)29:383-389, DOI 10.1007/s12190-008-0139-z.