Abstract
This paper presents a framework of iterative methods for finding a common solution to an equilibrium problem and a countable number of fixed point problems defined in a Hilbert space. A general strong convergence theorem is established under mild conditions. Two hybrid methods are derived from the proposed framework in coupling the fixed point iterations with the iterations of the proximal point method or the extragradient method, which are well-known methods for solving equilibrium problems. The strategy is to obtain the strong convergence from the weak convergence of the iterates without additional assumptions on the problem data. To achieve this aim, the solution set of the problem is outer approximated by a sequence of polyhedral subsets.
Similar content being viewed by others
References
Kimura, Y., Nakajo, K.: Viscosity approximations by the shrinking projection method in Hilbert spaces. Comput. Math. Appl. 63, 1400–1408 (2012)
Takahashi, W., Takeuchi, Y., Kubota, R.: Strong convergence theorems by hybrid methods for families of nonexpansive mappings in Hilbert spaces. J. Math. Anal. Appl. 341, 276–286 (2008)
Takahashi, W.: Viscosity approximation methods for countable families of nonexpansive mappings in Banach spaces. Nonlinear Anal. 70, 719–734 (2009)
Takahashi, W., Yao, J.-C.: Strong convergence theorems by hybrid methods for countable families of nonlinear operators in Banach spaces. J. Fixed Point Theory Appl. 11, 333–353 (2012)
Nakajo, K., Takahashi, W.: Strong convergence to common fixed points of families of nonexpansive mappings in Banach spaces. J. Math. Anal. Appl. 279, 248–264 (2003)
Nakajo, K., Shimoji, K., Takahashi, W.: Strong convergence to common fixed points of families of nonexpansive mappings in Banach spaces. J. Nonlinear Convex Anal. 8, 11–34 (2007)
Blum, E., Oettli, W.: From optimization and variational inequalities. Math. Stud. 63, 123–145 (1994)
Giannessi, F., Maugeri, A., Pardalos, P.: Equilibrium Problems: Nonsmooth Optimization and Variationnal Inequality Models. Kluwer Academic, Dordrecht (2001)
Mastroeni, G.: On auxiliary principle for equilibrium problems. In: Daniele, P., Giannessi, F., Maugeri, A. (eds.) Equilibrium Problems and Variational Models, pp. 289–298. Kluwer Academic, Dordrecht (2003)
Tran, D.Q., Le Dung, M., Nguyen, V.H.: Extragradient algorithms extended to equilibrium problems. Optimization 57, 749–776 (2008)
Fan, K.: A minimax inequality and applications. In: Shisha, O. (ed.) Inequality III, pp. 103–113. Academic Press, New York (1972)
Brézis, H., Nirenberg, L., Stampacchia, G.: A remark on Ky Fan’s minimax principle. Boll. Unione Mat. Ital. III VI, 129–132 (1972)
Bigi, G., Castellani, M., Pappalardo, M., Passacantando, M.: Existence and solution methods for equilibria. Eur. J. Oper. Res. 227, 1–11 (2013)
Iiduka, H.: A new iterative algorithm for the variational inequality problem over the fixed point set of a firmly nonexpansive mapping. Optimization 59, 873–885 (2010)
Sahu, D.R., Wong, N.C., Yao, J.C.: A unified hybrid iterative method for solving variational inequalities involving generalized pseudocontractive mappings. SIAM J. Control Optim. 50, 2335–2354 (2012)
Iusem, A.N., Sosa, W.: On the proximal point method for equilibrium problems in Hilbert spaces. Optimization 59, 1259–1274 (2010)
Nguyen, T.T.V., Strodiot, J.J., Nguyen, V.H.: A bundle method for solving equilibrium problems. Math. Program. 116, 529–552 (2009)
Nguyen, T.T.V., Strodiot, J.J., Nguyen, V.H.: The interior proximal extragradient method for solving equilibrium problems. J. Glob. Optim. 44, 175–192 (2009)
Ceng, L.C., Ansari, Q.H., Yao, J.C.: Hybrid pseudoviscosity approximation schemes for equilibrium problems and fixed point problems of infinitely many nonexpansive mappings. Nonlinear Anal. Hybrid Syst. 4, 743–754 (2010)
Ceng, L.C., Guu, S.M., Hu, H.Y., Yao, J.C.: Hybrid shrinking projection method for a generalized equilibrium problem, a maximal monotone operator and a countable family of relatively nonexpansive mappings. Comput. Math. Appl. 61, 2468–2479 (2011)
Ceng, L.C., Petrusel, A., Lee, C., Wong, M.M.: Two extragradient approximation methods for variational inequalities and fixed point problems of strict pseudo-contractions. Taiwan. J. Math. 13, 607–632 (2009)
Vuong, P.T., Strodiot, J.J., Nguyen, V.H.: Extragradient methods and linesearch algorithms for solving Ky Fan inequalities and fixed point problems. J. Optim. Theory Appl. 155, 605–627 (2012)
Vuong, P.T., Strodiot, J.J., Nguyen, V.H.: On extragradient-viscosity methods for solving equilibrium and fixed point problems in a Hilbert space. Optimization (2013). doi:10.1080/02331934.2012.759327
Strodiot, J.J., Nguyen, V.H., Vuong, P.T.: Strong convergence of two hybrid extragradient methods for solving equilibrium and fixed point problems. Vietnam J. Math. 40, 371–389 (2012)
Peng, J.-W., Yao, J.-C.: Some new iterative algorithms for generalized mixed equilibrium problems with strict pseudo-contractions and monotone mappings. Taiwan. J. Math. 13, 1537–1582 (2009)
Peng, J.-W., Yao, J.-C.: Strong convergence theorems of iterative scheme based on the extragradient method for mixed equilibrium problems and fixed point problems. Math. Comput. Model. 49, 1816–1828 (2009)
Shehu, Y.: Hybrid iterative scheme for fixed point problem, infinite systems of equilibrium problems and variational inequality problems. Comput. Math. Appl. 63, 1089–1103 (2012)
Yao, Y., Postolache, M.: Iterative methods for pseudomonotone variational inequalities and fixed-point problems. J. Optim. Theory Appl. 155, 273–287 (2012)
Opial, Z.: Weak convergence of the sequence of successive approximations for nonexpansive mappings. Bull. Am. Math. Soc. 73, 591–597 (1967)
Jaiboon, C., Kumam, P.: Strong convergence theorems for solving equilibrium problems and fixed point problems of ξ-strict pseudo-contraction mappings by two hybrid projection methods. J. Comput. Appl. Math. 230, 722–732 (2010)
Bauschke, H.H., Combettes, P.L.: A weak-to-strong convergence principle for Fejér-monotone methods in Hilbert spaces. Math. Oper. Res. 26, 248–264 (2001)
Martinez-Yanes, C., Xu, H.K.: Strong convergence of the CQ method for fixed point iteration processes. Nonlinear Anal. 64, 2400–2411 (2006)
Combettes, P.L., Hirstoaga, S.A.: Equilibrium programming in Hilbert spaces. J. Nonlinear Convex Anal. 6, 117–136 (2005)
Mordukhovich, B., Panicucci, B., Pappalardo, M., Passacantando, M.: Hybrid proximal methods for equilibrium problems. Optim. Lett. 6, 1535–1550 (2012)
Acknowledgements
The authors would like to thank the Editor, the Associate Editor, and the two anonymous referees for their comments and suggestions on improving significantly the presentation of an earlier version of the paper. This research is funded by the Department of Science and Technology at Ho Chi Minh City, Vietnam. Computing resources and support provided by the Institute for Computational Science and Technology—Ho Chi Minh City (ICST) is gratefully acknowledged. The work of Thi Thu Van Nguyen is also supported by the Vietnam National University at HCMC.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Jen-Chih Yao.
Rights and permissions
About this article
Cite this article
Nguyen, T.T.V., Strodiot, J.J. & Nguyen, V.H. Hybrid Methods for Solving Simultaneously an Equilibrium Problem and Countably Many Fixed Point Problems in a Hilbert Space. J Optim Theory Appl 160, 809–831 (2014). https://doi.org/10.1007/s10957-013-0400-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10957-013-0400-y