Mathematical Problems in Engineering
Volume 2011 (2011), Article ID 648617, 25 pages
doi:10.1155/2011/648617
Research Article

Hybrid Algorithms for Minimization Problems over the Solutions of Generalized Mixed Equilibrium and Variational Inclusion Problems

Department of Mathematics, Faculty of Science, King Mongkut's University of Technology Thonburi (KMUTT), Bangmod, Thrungkru, Bangkok 10140, Thailand

Received 3 March 2011; Accepted 21 June 2011

Academic Editor: Bin Liu

Copyright © 2011 Thanyarat Jitpeera and Poom Kumam. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We introduce a new general hybrid iterative algorithm for finding a common element of the set of solution of fixed point for a nonexpansive mapping, the set of solution of generalized mixed equilibrium problem, and the set of solution of the variational inclusion for a β-inverse-strongly monotone mapping in a real Hilbert space. We prove that the sequence converges strongly to a common element of the above three sets under some mild conditions. Our results improve and extend the corresponding results of Marino and Xu (2006), Yao and Liou (2010), Tan and Chang (2011), and other authors.

1. Introduction

In the theory of variational inequalities, variational inclusions, and equilibrium problems, the development of an efficient and implementable iterative algorithm is interesting and important. The important generalization of variational inequalities called variational inclusions, have been extensively studied and generalized in different directions to study a wide class of problems arising in mechanics, optimization, nonlinear programming, economics, finance, and applied sciences.

Equilibrium theory represents an important area of mathematical sciences such as optimization, operations research, game theory, complementarity problems, financial mathematics, and mechanics. Equilibrium problems include variational inequalities, optimization problems, Nash equilibria problems, saddle point problems, fixed point problems, and complementarity problems as special cases; for example, see the references herein. Let 𝐶 be a closed convex subset of a real Hilbert space 𝐻 with the inner product , and the norm . Let 𝐹 be a bifunction of 𝐶 × 𝐶 into , where is the set of real numbers, Φ 𝐶 𝐻 be a mapping and 𝜑 𝐶 be a real-valued function. The generalized mixed equilibrium problem for finding 𝑥 𝐶 such that 𝐹 ( 𝑥 , 𝑦 ) + Φ 𝑥 , 𝑦 𝑥 + 𝜑 ( 𝑦 ) 𝜑 ( 𝑥 ) 0 , 𝑦 𝐶 . ( 1 . 1 ) The set of solutions of (1.1) is denoted by G M E P ( 𝐹 , 𝜑 , Φ ) , that is G M E P ( 𝐹 , 𝜑 , Φ ) = { 𝑥 𝐶 𝐹 ( 𝑥 , 𝑦 ) + Φ 𝑥 , 𝑦 𝑥 + 𝜑 ( 𝑦 ) 𝜑 ( 𝑥 ) 0 , 𝑦 𝐶 } . ( 1 . 2 ) If Φ 0 and 𝜑 0 , the problem (1.1) is reduced into the equilibrium problem [1] for finding 𝑥 𝐶 such that 𝐹 ( 𝑥 , 𝑦 ) 0 , 𝑦 𝐶 . ( 1 . 3 ) The set of solutions of (1.3) is denoted by E P ( 𝐹 ) . This problem contains fixed point problems, includes as special cases numerous problems in physics, optimization, and economics. Some methods have been proposed to solve the equilibrium problem, please consult [24].

If 𝐹 0 and 𝜑 0 , the problem (1.1) is reduced into the Hartmann-Stampacchia variational inequality [5] for finding 𝑥 𝐶 such that Φ 𝑥 , 𝑦 𝑥 0 , 𝑦 𝐶 . ( 1 . 4 ) The set of solutions of (1.4) is denoted by V I ( 𝐶 , Φ ) . The variational inequality has been extensively studied in the literature [6].

If 𝐹 0 and Φ 0 , the problem (1.1) is reduced into the minimize problem for finding 𝑥 𝐶 such that 𝜑 ( 𝑦 ) 𝜑 ( 𝑥 ) 0 , 𝑦 𝐶 . ( 1 . 5 ) The set of solutions of (1.5) is denoted by A r g m i n ( 𝜑 ) .

A typical problem is to minimize a quadratic function over the set of the fixed points of a nonexpansive mapping on a real Hilbert space 𝐻 : 1 𝜃 ( 𝑥 ) = 2 𝐴 𝑥 , 𝑥 𝑥 , 𝑦 , 𝑥 𝐹 ( 𝑆 ) , ( 1 . 6 ) where 𝐴 is a linear bounded operator, 𝐹 ( 𝑆 ) is the fixed point set of a nonexpansive mapping 𝑆 , and 𝑦 is a given point in 𝐻 [7].

Recall, a mapping 𝑆 𝐶 𝐶 is said to be nonexpansive if 𝑆 𝑥 𝑆 𝑦 𝑥 𝑦 , ( 1 . 7 ) for all 𝑥 , 𝑦 𝐶 . If 𝐶 is bounded closed convex and 𝑆 is a nonexpansive mapping of 𝐶 into itself, then 𝐹 ( 𝑆 ) is nonempty [8]. We denote weak convergence and strongly convergence by notations and , respectively. A mapping 𝐴 of 𝐶 into 𝐻 is called monotone if 𝐴 𝑥 𝐴 𝑦 , 𝑥 𝑦 0 , ( 1 . 8 ) for all 𝑥 , 𝑦 𝐶 . A mapping 𝐴 of 𝐶 into 𝐻 is called 𝛼 - inverse-strongly monotone if there exists a positive real number 𝛼 such that 𝐴 𝑥 𝐴 𝑦 , 𝑥 𝑦 𝛼 𝐴 𝑥 𝐴 𝑦 2 , ( 1 . 9 ) for all 𝑥 , 𝑦 𝐶 . It is obvious that any 𝛼 -inverse-strongly monotone mappings 𝐴 is monotone and Lipschitz continuous mapping. A linear bounded operator 𝐴 is strongly positive if there exists a constant 𝛾 > 0 with the property 𝐴 𝑥 , 𝑥 𝛾 𝑥 2 , ( 1 . 1 0 ) for all 𝑥 𝐻 . A self-mapping 𝑓 𝐶 𝐶 is a contraction on 𝐶 if there exists a constant 𝛼 ( 0 , 1 ) such that 𝑓 ( 𝑥 ) 𝑓 ( 𝑦 ) 𝛼 𝑥 𝑦 , ( 1 . 1 1 ) for all 𝑥 , 𝑦 𝐶 . We use Π 𝐶 to denote the collection of all contraction on C. Note that each 𝑓 Π 𝐶 has a unique fixed point in 𝐶 .

Iterative methods for nonexpansive mappings have recently been applied to solve convex minimization problems. Convex minimization problems have a great impact and influence in the development of almost all branches of pure and applied sciences. Let 𝐵 𝐻 𝐻 be a single-valued nonlinear mapping and 𝑀 𝐻 2 𝐻 be a set-valued mapping. The variational inclusion problem is to find 𝑥 𝐻 such that 𝜃 𝐵 ( 𝑥 ) + 𝑀 ( 𝑥 ) , ( 1 . 1 2 ) where 𝜃 is the zero vector in 𝐻 . The set of solutions of problem (1.12) is denoted by 𝐼 ( 𝐵 , 𝑀 ) . The variational inclusion has been extensively studied in the literature. See, for example, [912] and the reference therein.

A set-valued mapping 𝑀 𝐻 2 𝐻 is called monotone if for all 𝑥 , 𝑦 𝐻 , 𝑓 𝑀 ( 𝑥 ) and 𝑔 𝑀 ( 𝑦 ) imply 𝑥 𝑦 , 𝑓 𝑔 0 . A monotone mapping 𝑀 is maximal if its graph 𝐺 ( 𝑀 ) = { ( 𝑓 , 𝑥 ) 𝐻 × 𝐻 𝑓 𝑀 ( 𝑥 ) } of 𝑀 is not properly contained in the graph of any other monotone mapping. It is known that a monotone mapping 𝑀 is maximal if and only if for ( 𝑥 , 𝑓 ) 𝐻 × 𝐻 , 𝑥 𝑦 , 𝑓 𝑔 0 for all ( 𝑦 , 𝑔 ) 𝐺 ( 𝑀 ) imply 𝑓 𝑀 ( 𝑥 ) .

Let 𝐵 be an inverse-strongly monotone mapping of 𝐶 into 𝐻 and let 𝑁 𝐶 𝑣 be normal cone to 𝐶 at 𝑣 𝐶 , that is, 𝑁 𝐶 𝑣 = { 𝑤 𝐻 𝑣 𝑢 , 𝑤 0 , 𝑢 𝐶 } , and define 𝑀 𝑣 = 𝐵 𝑣 + 𝑁 𝐶 𝑣 , i f 𝑣 𝐶 , , i f 𝑣 𝐶 . ( 1 . 1 3 ) Then 𝑀 is a maximal monotone and 𝜃 𝑀 𝑣 if and only if 𝑣 V I ( 𝐶 , 𝐵 ) [13].

Let 𝑀 𝐻 2 𝐻 be a set-valued maximal monotone mapping, then the single-valued mapping 𝐽 𝑀 , 𝜆 𝐻 𝐻 defined by 𝐽 𝑀 , 𝜆 ( 𝑥 ) = ( 𝐼 + 𝜆 𝑀 ) 1 ( 𝑥 ) , 𝑥 𝐻 ( 1 . 1 4 ) is called the resolvent operator associated with 𝑀 , where 𝜆 is any positive number and 𝐼 is the identity mapping. It is worth mentioning that the resolvent operator is nonexpansive, 1-inverse-strongly monotone, and that a solution of problem (1.12) is a fixed point of the operator 𝐽 𝑀 , 𝜆 ( 𝐼 𝜆 𝐵 ) for all 𝜆 > 0 , see [14], that is, 𝐼 ( 𝐵 , 𝑀 ) = 𝐹 ( 𝐽 𝑀 , 𝜆 ( 𝐼 𝜆 𝐵 ) ) , 𝜆 > 0 .

In 2000, Moudafi [15] introduced the viscosity approximation method for nonexpansive mapping and proved that if 𝐻 is a real Hilbert space, the sequence { 𝑥 𝑛 } defined by the iterative method below, with the initial guess 𝑥 0 𝐶 chosen arbitrarily, 𝑥 𝑛 + 1 = 𝛼 𝑛 𝑓 𝑥 𝑛 + 1 𝛼 𝑛 𝑆 𝑥 𝑛 , 𝑛 0 , ( 1 . 1 5 ) where { 𝛼 𝑛 } ( 0 , 1 ) satisfies certain conditions, converges strongly to a fixed point of 𝑆 (say 𝑥 𝐶 ) which is the unique solution of the following variational inequality: ( 𝐼 𝑓 ) 𝑥 , 𝑥 𝑥 0 , 𝑥 𝐹 ( 𝑆 ) . ( 1 . 1 6 )

In 2006, Marino and Xu [7] introduced a general iterative method for nonexpansive mapping. They defined the sequence { 𝑥 𝑛 } generated by the algorithm 𝑥 0 𝐶 , 𝑥 𝑛 + 1 = 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑥 𝑛 , 𝑛 0 , ( 1 . 1 7 ) where { 𝛼 𝑛 } ( 0 , 1 ) and 𝐴 is a strongly positive linear bounded operator. They prove that if 𝐶 = 𝐻 and the sequence { 𝛼 𝑛 } satisfies appropriate conditions, then the sequence { 𝑥 𝑛 } generated by (1.17) converges strongly to a fixed point of 𝑆 (say 𝑥 𝐻 ) which is the unique solution of the following variational inequality: ( 𝐴 𝛾 𝑓 ) 𝑥 , 𝑥 𝑥 0 , 𝑥 𝐹 ( 𝑆 ) , ( 1 . 1 8 ) which is the optimality condition for the minimization problem m i n 𝑥 𝐹 ( 𝑆 ) E P ( 𝐹 ) 1 2 𝐴 𝑥 , 𝑥 ( 𝑥 ) , ( 1 . 1 9 ) where is a potential function for 𝛾 𝑓 (i.e., ( 𝑥 ) = 𝛾 𝑓 ( 𝑥 ) for 𝑥 𝐻 ).

In 2010, Yao and Liou [16] introduced the following composite iterative scheme in a real Hilbert space: 𝑥 0 𝐶 𝑥 𝑛 + 1 = 𝜇 𝑛 𝑃 𝐶 𝛼 𝑛 𝑓 𝑥 𝑛 + 1 𝛼 𝑛 𝑆 𝑥 𝑛 + 1 𝜇 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 𝐴 𝑥 𝑛 , ( 1 . 2 0 ) for all 𝑛 , where { 𝛼 𝑛 } , { 𝜇 𝑛 } [ 0 , 1 ) . Furthermore, they proved { 𝑥 𝑛 } and { 𝑢 𝑛 } converge strongly to the same point 𝑧 𝐹 ( 𝑆 ) E P ( 𝐹 ) , where 𝑃 𝐶 is the projection of 𝐻 onto 𝐶 .

In 2011, Tan and Chang [11] introduced the following iterative process for { 𝑇 𝑛 𝐶 𝐶 } be a sequence of nonexpansive mappings. Let { 𝑥 𝑛 } be the sequence defined by 𝑥 𝑛 + 1 = 𝛼 𝑛 𝑥 𝑛 + 1 𝛼 𝑛 𝑆 𝑃 𝐶 1 𝑡 𝑛 𝐽 𝑀 , 𝜆 ( 𝐼 𝜆 𝐴 ) 𝑇 𝜇 𝑥 ( 𝐼 𝜇 𝐵 ) 𝑛 , 𝑛 0 , ( 1 . 2 1 ) where { 𝛼 𝑛 } ( 0 , 1 ) , 𝜆 ( 0 , 2 𝛼 ] and 𝜇 ( 0 , 2 𝛽 ] . Then, the sequence { 𝑥 𝑛 } defined by (1.21) converges strongly to a common element of the set of fixed points of nonexpansive mapping, the set of solution of the variational inequality and the generalized equilibrium problem.

In this paper, we modify the iterative methods (1.17), (1.20), and (1.21) by purposing the following new general viscosity iterative method: 𝑥 0 𝐶 , 𝑥 𝑛 + 1 = 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝐽 𝑀 , 𝜆 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 + 1 𝜉 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 , ( 1 . 2 2 ) for all 𝑛 , where { 𝛼 𝑛 } , { 𝜉 𝑛 } ( 0 , 1 ) , 𝑟 ( 0 , 2 𝜎 ) , and 𝜆 ( 0 , 2 𝛽 ) satisfy some appropriate conditions. Consequently, we show that under some control conditions the sequence { 𝑥 𝑛 } strongly converge to a common element of the set of fixed points of nonexpansive mapping, the solution of the generalized mixed equilibrium problem, and the set of solution of the variational inclusion in a real Hilbert space.

2. Preliminaries

Let 𝐻 be a real Hilbert space and 𝐶 be a nonempty closed convex subset of 𝐻 . Recall that the (nearest point) projection 𝑃 𝐶 from 𝐻 onto 𝐶 assigns to each 𝑥 𝐻 , the unique point in 𝑃 𝐶 𝑥 𝐶 satisfying the property 𝑥 𝑃 𝐶 𝑥 = m i n 𝑦 𝐶 𝑥 𝑦 . ( 2 . 1 ) The following characterizes the projection 𝑃 𝐶 . We recall some lemmas which will be needed in the rest of this paper.

Lemma 2.1. The function 𝑢 𝐶 is a solution of the variational inequality (1.4) if and only if 𝑢 𝐶 satisfies the relation 𝑢 = 𝑃 𝐶 ( 𝑢 𝜆 Φ 𝑢 ) for all 𝜆 > 0 .

Lemma 2.2. For a given 𝑧 𝐻 , 𝑢 𝐶 , 𝑢 = 𝑃 𝐶 𝑧 𝑢 𝑧 , 𝑣 𝑢 0 , 𝑣 𝐶 .
It is well known that 𝑃 𝐶 is a firmly nonexpansive mapping of 𝐻 onto 𝐶 and satisfies 𝑃 𝐶 𝑥 𝑃 𝐶 𝑦 2 𝑃 𝐶 𝑥 𝑃 𝐶 𝑦 , 𝑥 𝑦 , 𝑥 , 𝑦 𝐻 . ( 2 . 2 ) Moreover, 𝑃 𝐶 𝑥 is characterized by the following properties: 𝑃 𝐶 𝑥 𝐶 and for all 𝑥 𝐻 , 𝑦 𝐶 , 𝑥 𝑃 𝐶 𝑥 , 𝑦 𝑃 𝐶 𝑥 0 . ( 2 . 3 )

Lemma 2.3 (see [17]). Let 𝑀 𝐻 2 𝐻 be a maximal monotone mapping and let 𝐵 𝐻 𝐻 be a monotone and Lipschitz continuous mapping. Then the mapping 𝐿 = 𝑀 + 𝐵 𝐻 2 𝐻 is a maximal monotone mapping.

Lemma 2.4 (see [18]). Each Hilbert space 𝐻 satisfies Opial's condition, that is, for any sequence { 𝑥 𝑛 } 𝐻 with 𝑥 𝑛 𝑥 , the inequality l i m i n f 𝑛 𝑥 𝑛 𝑥 < l i m i n f 𝑛 𝑥 𝑛 𝑦 , hold for each 𝑦 𝐻 with 𝑦 𝑥 .

Lemma 2.5 (see [19]). Assume { 𝑎 𝑛 } is a sequence of nonnegative real numbers such that 𝑎 𝑛 + 1 1 𝛾 𝑛 𝑎 𝑛 + 𝛿 𝑛 𝛾 𝑛 , 𝑛 0 , ( 2 . 4 ) where { 𝛾 𝑛 } ( 0 , 1 ) and { 𝛿 𝑛 } is a sequence in such that (i) 𝑛 = 1 𝛾 𝑛 = .(ii) l i m s u p 𝑛 𝛿 𝑛 0 or 𝑛 = 1 | 𝛿 𝑛 𝛾 𝑛 | < .Then l i m 𝑛 𝑎 𝑛 = 0 .

Lemma 2.6 (see [20]). Let 𝐶 be a closed convex subset of a real Hilbert space 𝐻 and let 𝑇 𝐶 𝐶 be a nonexpansive mapping. Then 𝐼 𝑇 is demiclosed at zero, that is, 𝑥 𝑛 𝑥 , 𝑥 𝑛 𝑇 𝑥 𝑛 0 ( 2 . 5 ) implies 𝑥 = 𝑇 𝑥 .

For solving the generalized mixed equilibrium problem, let us assume that the bifunction 𝐹 𝐶 × 𝐶 , the nonlinear mapping Φ 𝐶 𝐻 is continuous monotone and 𝜑 𝐶 satisfies the following conditions: (A1) 𝐹 ( 𝑥 , 𝑥 ) = 0 for all 𝑥 𝐶 ; (A2) 𝐹 is monotone, that is, 𝐹 ( 𝑥 , 𝑦 ) + 𝐹 ( 𝑦 , 𝑥 ) 0 for any 𝑥 , 𝑦 𝐶 ; (A3)for each fixed 𝑦 𝐶 , 𝑥 𝐹 ( 𝑥 , 𝑦 ) is weakly upper semicontinuous; (A4)for each fixed 𝑥 𝐶 , 𝑦 𝐹 ( 𝑥 , 𝑦 ) is convex and lower semicontinuous; (B1)for each 𝑥 𝐶 and 𝑟 > 0 , there exist a bounded subset 𝐷 𝑥 𝐶 and 𝑦 𝑥 C such that for any 𝑧 𝐶 𝐷 𝑥 , 𝐹 𝑧 , 𝑦 𝑥 𝑦 + 𝜑 𝑥 1 𝜑 ( 𝑧 ) + 𝑟 𝑦 𝑥 𝑧 , 𝑧 𝑥 < 0 , ( 2 . 6 ) (B2) 𝐶 is a bounded set.

Lemma 2.7 (see [21]). Let 𝐶 be a nonempty closed convex subset of a real Hilbert space 𝐻 . Let 𝐹 𝐶 × 𝐶 be a bifunction mapping satisfies (A1)–(A4) and let 𝜑 𝐶 is convex and lower semicontinuous such that 𝐶 d o m 𝜑 . Assume that either (B1) or (B2) holds. For 𝑟 > 0 and 𝑥 𝐻 , then there exists 𝑢 𝐶 such that 1 𝐹 ( 𝑢 , 𝑦 ) + 𝜑 ( 𝑦 ) 𝜑 ( 𝑢 ) + 𝑟 𝑦 𝑢 , 𝑢 𝑥 . ( 2 . 7 ) Define a mapping 𝑇 𝑟 𝐻 𝐶 as follows: 𝑇 𝑟 1 ( 𝑥 ) = 𝑢 𝐶 𝐹 ( 𝑢 , 𝑦 ) + 𝜑 ( 𝑦 ) 𝜑 ( 𝑢 ) + 𝑟 , 𝑦 𝑢 , 𝑢 𝑥 0 , 𝑦 𝐶 ( 2 . 8 ) for all 𝑥 𝐻 . Then, the following hold: (i) 𝑇 𝑟 is single-valued; (ii) 𝑇 𝑟 is firmly nonexpansive, that is, for any 𝑥 , 𝑦 𝐻 , 𝑇 𝑟 𝑥 𝑇 𝑟 𝑦 2 𝑇 𝑟 𝑥 𝑇 𝑟 𝑦 , 𝑥 𝑦 ; (iii) 𝐹 ( 𝑇 𝑟 ) = M E P ( 𝐹 , 𝜑 ) ; (iv) M E P ( 𝐹 , 𝜑 ) is closed and convex.

Lemma 2.8 (see[7]). Assume 𝐴 is a strongly positive linear bounded operator on a Hilbert space 𝐻 with coefficient 𝛾 > 0 and 0 < 𝜌 𝐴 1 , then 𝐼 𝜌 𝐴 1 𝜌 𝛾 .

3. Strong Convergence Theorems

In this section, we show a strong convergence theorem which solves the problem of finding a common element of 𝐹 ( 𝑆 ) , G M E P ( 𝐹 , 𝜑 , Φ ) , and 𝐼 ( 𝐵 , 𝑀 ) of inverse-strongly monotone mappings in a Hilbert space.

Theorem 3.1. Let 𝐻 be a real Hilbert space, 𝐶 be a closed convex subset of 𝐻 . Let 𝐹 be a bifunction of 𝐶 × 𝐶 into satisfying (A1)–(A4) and 𝐵 , Φ 𝐶 𝐻 be 𝛽 , 𝜎 -inverse-strongly monotone mappings, 𝜑 𝐶 is convex and lower semicontinuous function, 𝑓 𝐶 𝐶 be a contraction with coefficient 𝛼 ( 0 < 𝛼 < 1 ) , 𝑀 𝐻 2 𝐻 be a maximal monotone mapping and 𝐴 be a strongly positive linear bounded operator of 𝐻 into itself with coefficient 𝛾 > 0 , assume that 0 < 𝛾 < 𝛾 / 𝛼 . Let 𝑆 be a nonexpansive mapping of 𝐻 into itself and assume that either (B1) or (B2) holds such that Θ = 𝐹 ( 𝑆 ) G M E P ( 𝐹 , 𝜑 , Φ ) 𝐼 ( 𝐵 , 𝑀 ) . ( 3 . 1 ) Suppose { 𝑥 𝑛 } is a sequences generated by the following algorithm 𝑥 0 𝐶 arbitrarily: 𝑥 𝑛 + 1 = 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝐽 𝑀 , 𝜆 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 + 1 𝜉 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 , ( 3 . 2 ) where { 𝛼 𝑛 } , { 𝜉 𝑛 } ( 0 , 1 ) , 𝜆 ( 0 , 2 𝛽 ) such that 0 < 𝑎 𝜆 𝑏 < 2 𝛽 and 𝑟 ( 0 , 2 𝜎 ) with 0 < 𝑐 𝑑 1 𝜎 satisfy the following conditions: (C1) l i m 𝑛 𝛼 𝑛 = 0 , Σ 𝑛 = 0 𝛼 𝑛 = and l i m 𝑛 ( 𝛼 𝑛 + 1 / 𝛼 𝑛 ) = 1 ,(C2) 0 < l i m i n f 𝑛 𝜉 𝑛 < l i m s u p 𝑛 𝜉 𝑛 < 1 and l i m 𝑛 ( ( 𝜉 𝑛 + 1 𝜉 𝑛 ) / 𝛼 𝑛 + 1 ) = 1 .
Then { 𝑥 𝑛 } converges strongly to 𝑞 Θ , where 𝑞 = 𝑃 Θ ( 𝛾 𝑓 + 𝐼 𝐴 ) ( 𝑞 ) which solves the following variational inequality: ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑝 𝑞 0 , 𝑝 Θ ( 3 . 3 ) which is the optimality condition for the minimization problem m i n 𝑞 Θ 1 2 𝐴 𝑞 , 𝑞 ( 𝑞 ) , ( 3 . 4 ) where is a potential function for 𝛾 𝑓 (i.e., ( 𝑞 ) = 𝛾 𝑓 ( 𝑞 ) for 𝑞 𝐻 ).

Proof. Because of condition (C1), we may assume without loss of generality, then 𝛼 𝑛 ( 0 , 𝐴 1 ) for all 𝑛 . By Lemma 2.8, we have 𝐼 𝛼 𝑛 𝐴 1 𝛼 𝑛 𝛾 . Next, we will assume that 𝐼 𝐴 1 𝛾 .
Step 1. We will show { 𝑥 𝑛 } , { 𝑢 𝑛 } are bounded.
Since 𝐵 , Φ are 𝛽 , 𝜎 -inverse-strongly monotone mappings, we have ( 𝐼 𝜆 𝐵 ) 𝑥 ( 𝐼 𝜆 𝐵 ) 𝑦 2 = ( 𝑥 𝑦 ) 𝜆 ( 𝐵 𝑥 𝐵 𝑦 ) 2 = 𝑥 𝑦 2 2 𝜆 𝑥 𝑦 , 𝐵 𝑥 𝐵 𝑦 + 𝜆 2 𝐵 𝑥 𝐵 𝑦 2 𝑥 𝑦 2 + 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝐵 𝑦 2 𝑥 𝑦 2 . ( 3 . 5 ) In similar way, we can obtain ( 𝐼 𝑟 Φ ) 𝑥 ( 𝐼 𝑟 Φ ) 𝑦 2 𝑥 𝑦 2 . ( 3 . 6 ) It is clear that if 0 < 𝜆 < 2 𝛽 , 0 < 𝑟 < 2 𝜎 , then 𝐼 𝜆 𝐵 , 𝐼 𝑟 Φ are all nonexpansive.
Put 𝑦 𝑛 = 𝐽 𝑀 , 𝜆 ( 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 ) , 𝑛 0 . It follows that 𝑦 𝑛 = 𝐽 𝑞 𝑀 , 𝜆 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 𝐽 𝑀 , 𝜆 𝑥 ( 𝑞 𝜆 𝐵 𝑞 ) 𝑛 . 𝑞 ( 3 . 7 ) By Lemma 2.7, we have 𝑢 𝑛 = 𝑇 𝑟 ( 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 ) for all 𝑛 0 . Then, we have 𝑢 𝑛 𝑞 2 = 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 𝑇 𝑟 ( 𝑞 𝑟 Φ 𝑞 ) 2 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 ( 𝑞 𝑟 Φ 𝑞 ) 2 𝑥 𝑛 𝑞 2 + 𝑟 ( 𝑟 2 𝜎 ) Φ 𝑥 𝑛 Φ 𝑞 2 𝑥 𝑛 𝑞 2 . ( 3 . 8 ) Put 𝑧 𝑛 = 𝑃 𝐶 [ 𝛼 𝑛 𝛾 𝑓 ( 𝑥 𝑛 ) + ( 𝐼 𝛼 𝑛 𝐴 ) 𝑆 𝑦 𝑛 ] for all 𝑛 0 . From (3.2), we deduce that 𝑥 𝑛 + 1 𝜉 𝑞 = 𝑛 𝑧 𝑛 + 𝑞 1 𝜉 𝑛 𝑢 𝑛 𝑞 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝑃 𝐶 𝑞 + 1 𝜉 𝑛 𝑢 𝑛 𝑞 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 + 𝑞 1 𝜉 𝑛 𝑢 𝑛 𝑞 = 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐴 𝑞 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 + 𝑞 1 𝜉 𝑛 𝑢 𝑛 𝑞 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 + 𝜉 𝑛 1 𝛼 𝑛 𝛾 𝑦 𝑛 + 𝑞 1 𝜉 𝑛 𝑢 𝑛 𝑞 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝛾 𝑓 ( 𝑞 ) + 𝜉 𝑛 𝛼 𝑛 ( 𝛾 𝑓 𝑞 ) 𝐴 𝑞 + 𝜉 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝑛 + 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝛼 𝑛 𝑞 + 𝜉 𝑛 𝛼 𝑛 ( 𝛾 𝑓 𝑞 ) 𝐴 𝑞 + 𝜉 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝑛 + 𝑞 1 𝜉 𝑛 𝑥 𝑛 = 𝑞 1 𝜉 𝛾 𝛾 𝛼 𝑛 𝛼 𝑛 𝑥 𝑛 𝑞 + 𝜉 𝑛 𝛼 𝑛 = 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 1 𝜉 𝛾 𝛾 𝛼 𝑛 𝛼 𝑛 𝑥 𝑛 + 𝑞 𝜉 𝛾 𝛾 𝛼 𝑛 𝛼 𝑛 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 𝑥 𝛾 𝛾 𝛼 m a x 𝑛 , ( 𝑞 𝛾 𝑓 𝑞 ) 𝐴 𝑞 . 𝛾 𝛾 𝛼 ( 3 . 9 ) It follows from induction that 𝑥 𝑛 𝑥 𝑞 m a x 0 , ( 𝑞 𝛾 𝑓 𝑞 ) 𝐴 𝑞 𝛾 𝛾 𝛼 , 𝑛 0 . ( 3 . 1 0 ) Therefore { 𝑥 𝑛 } is bounded, so are { 𝑦 𝑛 } , { 𝑆 𝑦 𝑛 } , { 𝐵 𝑥 𝑛 } , { 𝑓 ( 𝑥 𝑛 ) } , and { 𝐴 𝑆 𝑦 𝑛 } .
Step 2. We claim that l i m 𝑛 𝑥 𝑛 + 2 𝑥 𝑛 + 1 = 0 . From (3.2), we have 𝑥 𝑛 + 2 𝑥 𝑛 + 1 = 𝜉 𝑛 + 1 𝑧 𝑛 + 1 + 1 𝜉 𝑛 + 1 𝑢 𝑛 + 1 𝜉 𝑛 𝑧 𝑛 1 𝜉 𝑛 𝑢 𝑛 = 𝜉 𝑛 + 1 𝑧 𝑛 + 1 𝑧 𝑛 + 𝜉 𝑛 + 1 𝜉 𝑛 𝑧 𝑛 + 1 𝜉 𝑛 + 1 𝑢 𝑛 + 1 𝑢 𝑛 + 𝜉 𝑛 + 1 𝜉 𝑛 𝑢 𝑛 𝜉 𝑛 + 1 𝑧 𝑛 + 1 𝑧 𝑛 + 1 𝜉 𝑛 + 1 𝑢 𝑛 + 1 𝑢 𝑛 + | | 𝜉 𝑛 + 1 𝜉 𝑛 | | 𝑧 𝑛 + 𝑢 𝑛 . ( 3 . 1 1 ) We estimate 𝑢 𝑛 + 1 𝑢 𝑛 , so we have 𝑢 𝑛 + 1 𝑢 𝑛 = 𝑇 𝑟 𝑥 𝑛 + 1 𝑟 Φ 𝑥 𝑛 + 1 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 𝑥 𝑛 + 1 𝑟 Φ 𝑥 𝑛 + 1 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 𝑥 𝑛 + 1 𝑥 𝑛 . ( 3 . 1 2 ) Substituting (3.12) into (3.11) that 𝑥 𝑛 + 2 𝑥 𝑛 + 1 𝜉 𝑛 + 1 𝑧 𝑛 + 1 𝑧 𝑛 + 1 𝜉 𝑛 + 1 𝑥 𝑛 + 1 𝑥 𝑛 + | | 𝜉 𝑛 + 1 𝜉 𝑛 | | 𝑧 𝑛 + 𝑢 𝑛 . ( 3 . 1 3 ) We note that 𝑧 𝑛 + 1 𝑧 𝑛 = 𝑃 𝐶 𝛼 𝑛 + 1 𝑥 𝛾 𝑓 𝑛 + 1 + 𝐼 𝛼 𝑛 + 1 𝐴 𝑆 𝑦 𝑛 + 1 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝛼 𝑛 + 1 𝑥 𝛾 𝑓 𝑛 + 1 + 𝐼 𝛼 𝑛 + 1 𝐴 𝑆 𝑦 𝑛 + 1 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 = 𝛼 𝑛 + 1 𝛾 𝑓 𝑥 𝑛 + 1 𝑥 𝑓 𝑛 + 𝛼 𝑛 + 1 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 + 1 𝐴 𝑆 𝑦 𝑛 + 1 𝑆 𝑦 𝑛 + 𝛼 𝑛 𝛼 𝑛 + 1 𝐴 𝑆 𝑦 𝑛 𝛼 𝑛 + 1 𝑥 𝛾 𝛼 𝑛 + 1 𝑥 𝑛 + | | 𝛼 𝑛 + 1 𝛼 𝑛 | | 𝑥 𝛾 𝑓 𝑛 + 1 𝛼 𝑛 + 1 𝛾 𝑦 𝑛 + 1 𝑦 𝑛 + | | 𝛼 𝑛 + 1 𝛼 𝑛 | | 𝐴 𝑆 𝑦 𝑛 = 𝛼 𝑛 + 1 𝑥 𝛾 𝛼 𝑛 + 1 𝑥 𝑛 + | | 𝛼 𝑛 + 1 𝛼 𝑛 | | 𝑥 𝛾 𝑓 𝑛 + 𝐴 𝑆 𝑦 𝑛 + 1 𝛼 𝑛 + 1 𝛾 𝑦 𝑛 + 1 𝑦 𝑛 . ( 3 . 1 4 ) Next, we estimate 𝑦 𝑛 + 1 𝑦 𝑛 , then we get 𝑦 𝑛 + 1 𝑦 𝑛 = 𝐽 𝑀 , 𝜆 𝑥 𝑛 + 1 𝜆 𝐵 𝑥 𝑛 + 1 𝐽 𝑀 , 𝜆 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 𝑥 𝑛 + 1 𝜆 𝐵 𝑥 𝑛 + 1 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 𝑥 𝑛 + 1 𝑥 𝑛 . ( 3 . 1 5 ) Substituting (3.15) into (3.14), we obtain that 𝑧 𝑛 + 1 𝑧 𝑛 𝛼 𝑛 + 1 𝑥 𝛾 𝛼 𝑛 + 1 𝑥 𝑛 + | | 𝛼 𝑛 + 1 𝛼 𝑛 | | 𝑥 𝛾 𝑓 𝑛 + 𝐴 𝑆 𝑦 𝑛 + 1 𝛼 𝑛 + 1 𝛾 𝑥 𝑛 + 1 𝑥 𝑛 . ( 3 . 1 6 ) And substituting (3.12), (3.16) into (3.11), we get 𝑥 𝑛 + 2 𝑥 𝑛 + 1 𝜉 𝑛 + 1 𝛼 𝑛 + 1 𝑥 𝛾 𝛼 𝑛 + 1 𝑥 𝑛 + | | 𝛼 𝑛 + 1 𝛼 𝑛 | | 𝑥 𝛾 𝑓 𝑛 + 𝐴 𝑆 𝑦 𝑛 + 1 𝛼 𝑛 + 1 𝛾 𝑥 𝑛 + 1 𝑥 𝑛 + 1 𝜉 𝑛 + 1 𝑥 𝑛 + 1 𝑥 𝑛 + | | 𝜉 𝑛 + 1 𝜉 𝑛 | | 𝑧 𝑛 + 𝑢 𝑛 1 𝜉 𝛾 𝛾 𝛼 𝑛 + 1 𝛼 𝑛 + 1 𝑥 𝑛 + 1 𝑥 𝑛 + | | 𝛼 𝑛 + 1 𝛼 𝑛 | | + | | 𝜉 𝑛 + 1 𝜉 𝑛 | | 𝑀 , ( 3 . 1 7 ) where 𝑀 > 0 is a constant satisfying s u p 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐴 𝑆 𝑦 𝑛 , 𝑧 𝑛 + 𝑢 𝑛 𝑀 . ( 3 . 1 8 ) This together with (C1), (C2), and Lemma 2.5, implies that l i m 𝑛 𝑥 𝑛 + 2 𝑥 𝑛 + 1 = 0 . ( 3 . 1 9 ) From (3.15), we also have 𝑦 𝑛 + 1 𝑦 𝑛 0 as 𝑛 .Step 3. We show the following: (i) l i m 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 = 0 ; (ii) l i m 𝑛 Φ 𝑥 𝑛 Φ 𝑞 = 0 . For 𝑞 Ω and 𝑞 = 𝐽 𝑀 , 𝜆 ( 𝑞 𝜆 𝐵 𝑞 ) , then we get 𝑦 𝑛 𝑞 2 = 𝐽 𝑀 , 𝜆 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 𝐽 𝑀 , 𝜆 ( 𝑞 𝜆 𝐵 𝑞 ) 2 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 ( 𝑞 𝜆 𝐵 𝑞 ) 2 𝑥 𝑛 𝑞 2 + 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 . ( 3 . 2 0 ) It follows that 𝑧 𝑛 𝑞 2 = 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝑃 𝐶 ( 𝑞 ) 2 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐴 𝑞 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝑞 2 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 1 𝛼 𝑛 𝛾 𝑦 𝑛 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 𝑞 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 + 𝑞 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑞 2 + 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 + 𝑥 𝑞 𝑛 𝑞 2 + 1 𝛼 𝑛 𝛾 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 . ( 3 . 2 1 ) By the convexity of the norm , we have 𝑥 𝑛 + 1 𝑞 2 = 𝜉 𝑛 𝑧 𝑛 + 1 𝜉 𝑛 𝑢 𝑛 𝑞 2 = 𝜉 𝑛 𝑧 𝑛 + 𝑞 1 𝜉 𝑛 𝑢 𝑛 𝑞 2 𝜉 𝑛 𝑧 𝑛 𝑞 2 + 1 𝜉 𝑛 𝑢 𝑛 𝑞 2 . ( 3 . 2 2 ) Substituting (3.8), (3.21) into (3.22), we obtain 𝑥 𝑛 + 1 𝑞 2 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 + 𝑥 𝑞 𝑛 𝑞 2 + 1 𝛼 𝑛 𝛾 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 + 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 = 𝜉 𝑛 𝛼 𝑛 𝛾 𝑓 ( 𝑥 𝑛 ) 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 𝑞 + 𝜉 𝑛 𝑥 𝑛 𝑞 2 + 𝜉 𝑛 1 𝛼 𝑛 𝛾 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 + 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 . ( 3 . 2 3 ) So, we obtain 𝜉 𝑛 1 𝛼 𝑛 𝛾 𝜆 ( 2 𝛽 𝜆 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 𝜉 𝑛 𝛼 𝑛 𝛾 𝑓 ( 𝑥 𝑛 ) 𝐴 𝑞 2 + 𝜖 𝑛 + 𝑥 𝑛 𝑥 𝑛 + 1 𝑥 𝑛 + 𝑥 𝑞 𝑛 + 1 , 𝑞 ( 3 . 2 4 ) where 𝜖 𝑛 = 2 𝜉 𝑛 𝛼 𝑛 ( 1 𝛼 𝑛 𝛾 ) 𝛾 𝑓 ( 𝑥 𝑛 ) 𝐴 𝑞 𝑦 𝑛 𝑞 . Since condition (C1), (C2) and l i m 𝑛 𝑥 𝑛 + 1 𝑥 𝑛 = 0 then we obtain that 𝐵 𝑥 𝑛 𝐵 𝑞 0 as 𝑛 . We consider this inequality in (3.21) that 𝑧 𝑛 𝑞 2 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 1 𝛼 𝑛 𝛾 𝑦 𝑛 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 . 𝑞 ( 3 . 2 5 ) Substituting (3.20) into (3.25), we have 𝑧 𝑛 𝑞 2 𝛼 𝑛 𝛾 𝑓 ( 𝑥 𝑛 ) 𝐴 𝑞 2 + 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑞 2 + 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 𝑞 = 𝛼 𝑛 𝛾 𝑓 ( 𝑥 𝑛 ) 𝐴 𝑞 2 + 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑞 2 + 1 𝛼 𝑛 𝛾 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 𝑞 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 𝑥 𝑛 𝑞 2 + 1 𝛼 𝑛 𝛾 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 . 𝑞 ( 3 . 2 6 ) Substituting (3.8) and (3.26) into (3.22), we obtain 𝑥 𝑛 + 1 𝑞 2 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 𝑥 𝑛 𝑞 2 + 1 𝛼 𝑛 𝛾 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 + 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 + 𝑟 ( 𝑟 2 𝜎 ) Φ 𝑥 𝑛 Φ 𝑞 2 = 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 𝜉 𝑛 𝑥 𝑛 𝑞 2 + 𝜉 𝑛 1 𝛼 𝑛 𝛾 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 + 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 + 1 𝜉 𝑛 𝑟 ( 𝑟 2 𝜎 ) Φ 𝑥 𝑛 Φ 𝑞 2 . ( 3 . 2 7 ) So, we also have 1 𝜉 𝑛 𝑟 ( 2 𝜎 𝑟 ) Φ 𝑥 𝑛 Φ 𝑞 2 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 𝜖 𝑛 + 𝑥 𝑛 𝑥 𝑛 + 1 𝑥 𝑛 + 𝑥 𝑞 𝑛 + 1 𝑞 + 𝜉 𝑛 1 𝛼 𝑛 𝛾 𝜆 ( 𝜆 2 𝛽 ) 𝐵 𝑥 𝑛 𝐵 𝑞 2 , ( 3 . 2 8 ) where 𝜖 𝑛 = 2 𝜉 𝑛 𝛼 𝑛 ( 1 𝛼 𝑛 𝛾 ) 𝛾 𝑓 ( 𝑥 𝑛 ) 𝐴 𝑞 𝑦 𝑛 𝑞 . Since condition (C1), (C2), l i m 𝑛 𝑥 𝑛 + 1 𝑥 𝑛 = 0 and l i m 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 = 0 then we obtain that Φ 𝑥 𝑛 Φ 𝑞 0 as 𝑛 .Step 4. We show the following:(i) l i m 𝑛 𝑥 𝑛 𝑢 𝑛 = 0 ; (ii) l i m 𝑛 𝑥 𝑛 𝑦 𝑛 = 0 ; (iii) l i m 𝑛 𝑦 𝑛 𝑆 𝑦 𝑛 = 0 . Since 𝑇 𝑟 is firmly nonexpansive, we observe that 𝑢 𝑛 𝑞 2 = 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 𝑇 𝑟 ( 𝑞 𝑟 Φ 𝑞 ) 2 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 ( 𝑞 𝑟 Φ 𝑞 ) , 𝑢 𝑛 = 1 𝑞 2 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 ( 𝑞 𝑟 Φ 𝑞 ) 2 + 𝑢 𝑛 𝑞 2 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 𝑢 ( 𝑞 𝑟 Φ 𝑞 ) 𝑛 𝑞 2 1 2 𝑥 𝑛 𝑞 2 + 𝑢 𝑛 𝑞 2 𝑥 𝑛 𝑢 𝑛 𝑟 Φ 𝑥 𝑛 Φ 𝑞 2 = 1 2 𝑥 𝑛 𝑞 2 + 𝑢 𝑛 𝑞 2 𝑥 𝑛 𝑢 𝑛 2 + 2 𝑟 Φ 𝑥 𝑛 Φ 𝑞 , 𝑥 𝑛 𝑢 𝑛 𝑟 2 Φ 𝑥 𝑛 Φ 𝑞 2 . ( 3 . 2 9 ) Hence, we have 𝑢 𝑛 𝑞 2 𝑥 𝑛 𝑞 2 𝑥 𝑛 𝑢 𝑛 2 + 2 𝑟 Φ 𝑥 𝑛 𝑥 Φ 𝑞 𝑛 𝑢 𝑛 . ( 3 . 3 0 ) Since 𝐽 𝑀 , 𝜆 is 1-inverse-strongly monotone, we have 𝑦 𝑛 𝑞 2 = 𝐽 𝑀 , 𝜆 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 𝐽 𝑀 , 𝜆 ( 𝑞 𝜆 𝐵 𝑞 ) 2 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 ( 𝑞 𝜆 𝐵 𝑞 ) , 𝑦 𝑛 = 1 𝑞 2 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 ( 𝑞 𝜆 𝐵 𝑞 ) 2 + 𝑦 𝑛 𝑞 2 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 𝑦 ( 𝑞 𝜆 𝐵 𝑞 ) 𝑛 𝑞 2 1 2 𝑥 𝑛 𝑞 2 + 𝑦 𝑛 𝑞 2 𝑥 𝑛 𝑦 𝑛 𝜆 𝐵 𝑥 𝑛 𝐵 𝑞 2 = 1 2 𝑥 𝑛 𝑞 2 + 𝑦 𝑛 𝑞 2 𝑥 𝑛 𝑦 𝑛 2 + 2 𝜆 𝑥 𝑛 𝑦 𝑛 , 𝐵 𝑥 𝑛 𝐵 𝑞 𝜆 2 𝐵 𝑥 𝑛 𝐵 𝑞 2 , ( 3 . 3 1 ) which implies that 𝑦 𝑛 𝑞 2 𝑥 𝑛 𝑞 2 𝑥 𝑛 𝑦 𝑛 2 𝑥 + 2 𝜆 𝑛 𝑦 𝑛 𝐵 𝑥 𝑛 . 𝐵 𝑞 ( 3 . 3 2 ) Substituting (3.32) into (3.25), we have 𝑧 𝑛 𝑞 2 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑞 2 𝑥 𝑛 𝑦 𝑛 2 𝑥 + 2 𝜆 𝑛 𝑦 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 𝑞 = 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑞 2 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑦 𝑛 2 + 2 𝜆 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑦 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 . 𝑞 ( 3 . 3 3 ) Substituting (3.30) and (3.33) into (3.22), we obtain 𝑥 𝑛 + 1 𝑞 2 𝜉 𝑛 𝑧 𝑛 𝑞 2 + 1 𝜉 𝑛 𝑢 𝑛 𝑞 2 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑞 2 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑦 𝑛 2 + 2 𝜆 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑦 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 + 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝑥 𝑛 𝑢 𝑛 2 + 2 𝑟 Φ 𝑥 𝑛 𝑥 Φ 𝑞 𝑛 𝑢 𝑛 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 𝑥 𝑛 𝑞 2 𝑥 𝑛 𝑦 𝑛 2 + 2 𝜆 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑦 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 + 2 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 + 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝑥 𝑛 𝑢 𝑛 2 + 2 𝑟 Φ 𝑥 𝑛 𝑥 Φ 𝑞 𝑛 𝑢 𝑛 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝑥 𝑛 𝑦 𝑛 2 + 2 𝜆 𝜉 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑦 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 + 2 𝜉 𝑛 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝑦 𝐴 𝑞 𝑛 + 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝑥 𝑛 𝑢 𝑛 2 + 2 𝑟 1 𝜉 𝑛 Φ 𝑥 𝑛 𝑥 Φ 𝑞 𝑛 𝑢 𝑛 . ( 3 . 3 4 ) Then, we derive 𝑥 𝑛 𝑢 𝑛 2 + 𝑥 𝑛 𝑦 𝑛 2 = 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 𝑥 𝑛 𝑞 2 𝑥 𝑛 + 1 𝑞 2 + 2 𝜉 𝑛 𝜆 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑦 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 + 2 𝜉 𝑛 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 𝑦 𝑛 𝑞 + 2 𝑟 1 𝜉 𝑛 Φ 𝑥 𝑛 𝑥 Φ 𝑞 𝑛 𝑢 𝑛 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 𝑥 𝑛 + 1 𝑥 𝑛 𝑥 𝑛 + 𝑥 𝑞 𝑛 + 1 𝑞 + 2 𝜉 𝑛 𝜆 1 𝛼 𝑛 𝛾 𝑥 𝑛 𝑦 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 + 2 𝜉 𝑛 𝛼 𝑛 1 𝛼 𝑛 𝛾 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 𝑦 𝑛 𝑞 + 2 𝑟 1 𝜉 𝑛 Φ 𝑥 𝑛 𝑥 Φ 𝑞 𝑛 𝑢 𝑛 . ( 3 . 3 5 ) By condition (C1), (C2), l i m 𝑛 𝑥 𝑛 𝑥 𝑛 + 1 = 0 , l i m 𝑛 Φ 𝑥 𝑛 Φ 𝑞 = 0 , and l i m 𝑛 𝐵 𝑥 𝑛 𝐵 𝑞 = 0 . So, we have 𝑥 𝑛 𝑢 𝑛 0 , 𝑥 𝑛 𝑦 𝑛 0 as 𝑛 . It follows that 𝑢 𝑛 𝑦 𝑛 𝑥 𝑛 𝑢 𝑛 + 𝑥 𝑛 𝑦 𝑛 0 , a s 𝑛 . ( 3 . 3 6 ) We note that 𝑥 𝑛 + 1 𝑥 𝑛 = 𝜉 𝑛 ( 𝑧 𝑛 𝑥 𝑛 ) + ( 1 𝜉 𝑛 ) ( 𝑢 𝑛 𝑥 𝑛 ) . From l i m 𝑛 𝑥 𝑛 𝑢 𝑛 = 0 , l i m 𝑛 𝑥 𝑛 + 1 𝑥 𝑛 = 0 , and hence l i m 𝑛 𝑧 𝑛 𝑥 𝑛 = 0 . ( 3 . 3 7 ) Since 𝑧 𝑛 𝑦 𝑛 𝑧 𝑛 𝑥 𝑛 + 𝑥 𝑛 𝑦 𝑛 . ( 3 . 3 8 ) So, by (3.37) and l i m 𝑛 𝑥 𝑛 𝑦 𝑛 = 0 , we obtain l i m 𝑛 𝑧 𝑛 𝑦 𝑛 = 0 . ( 3 . 3 9 ) Therefore, we observe that 𝑆 𝑦 𝑛 𝑧 𝑛 𝑆 𝑦 𝑛 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝑆 𝑦 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑆 𝑦 𝑛 . ( 3 . 4 0 ) By condition (C1), we have 𝑆 𝑦 𝑛 𝑧 𝑛 0 as 𝑛 . Next, we observe that 𝑆 𝑦 𝑛 𝑦 𝑛 𝑆 𝑦 𝑛 𝑧 𝑛 + 𝑧 𝑛 𝑦 𝑛 . ( 3 . 4 1 ) By (3.39) and (3.40), we have 𝑆 𝑦 𝑛 𝑦 𝑛 0 as 𝑛 .Step 5. We show that 𝑞 Θ = 𝐹 ( 𝑆 ) G M E P ( 𝐹 , 𝜑 , Φ ) 𝐼 ( 𝐵 , 𝑀 ) and l i m s u p 𝑛 ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑆 𝑦 𝑛 𝑞 0 . It is easy to see that 𝑃 Θ ( 𝛾 𝑓 + ( 𝐼 𝐴 ) ) is a contraction of 𝐻 into itself. Indeed, since 0 < 𝛾 < 𝛾 / 𝛼 we have 𝑃 Θ ( 𝛾 𝑓 + ( 𝐼 𝐴 ) ) 𝑥 𝑃 Θ | | | | ( 𝛾 𝑓 + ( 𝐼 𝐴 ) ) 𝑦 ( 𝛾 𝑓 + ( 𝐼 𝐴 ) ) 𝑥 ( 𝛾 𝑓 + ( 𝐼 𝐴 ) ) 𝑦 𝛾 𝑓 ( 𝑥 ) 𝑓 ( 𝑦 ) + 𝐼 𝐴 𝑥 𝑦 𝛾 𝛼 𝑥 𝑦 + 1 𝛾 = 𝑥 𝑦 1 𝛾 + 𝛾 𝛼 𝑥 𝑦 . ( 3 . 4 2 ) Since 𝐻 is complete, there exists a unique fixed point 𝑞 𝐻 such that 𝑞 = 𝑃 Θ ( 𝛾 𝑓 + ( 𝐼 𝐴 ) ) ( 𝑞 ) . By Lemma 2.2, we obtain that ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑤 𝑞 0 for all 𝑤 Θ .
Next, we show that l i m s u p 𝑛 ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑆 𝑦 𝑛 𝑞 0 , where 𝑞 = 𝑃 Θ ( 𝛾 𝑓 + 𝐼 𝐴 ) ( 𝑞 ) is the unique solution of the variational inequality ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑝 𝑞 0 , f o r a l l 𝑝 Θ . We can choose a subsequence { 𝑦 𝑛 𝑖 } of { 𝑦 𝑛 } such that l i m s u p 𝑛 ( 𝛾 𝑓 𝐴 ) 𝑞 , S 𝑦 𝑛 𝑞 = l i m 𝑖 ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑆 𝑦 𝑛 𝑖 . 𝑞 ( 3 . 4 3 ) Since { 𝑦 𝑛 𝑖 } is bounded, there exists a subsequence { 𝑦 𝑛 𝑖 𝑗 } of { 𝑦 𝑛 𝑖 } which converges weakly to 𝑤 . We may assume without loss of generality that 𝑦 𝑛 𝑖 𝑤 . We claim that 𝑤 Θ , since l i m 𝑛 𝑦 𝑛 𝑆 𝑦 𝑛 = 0 and by Lemma 2.6, we have 𝑤 𝐹 ( 𝑆 ) .
Next, we show that 𝑤 G M E P ( 𝐹 , 𝜑 , Φ ) . Since 𝑢 𝑛 = 𝑇 𝑟 ( 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 ) , we know that 𝐹 𝑢 𝑛 𝑢 , 𝑦 + 𝜑 ( 𝑦 ) 𝜑 𝑛 + Φ 𝑥 𝑛 , 𝑦 𝑢 𝑛 1 + 𝑟 𝑦 𝑢 𝑛 , 𝑢 𝑛 𝑥 𝑛 0 , 𝑦 𝐶 . ( 3 . 4 4 ) It follows by (A2) that 𝑢 𝜑 ( 𝑦 ) 𝜑 𝑛 + Φ 𝑥 𝑛 , 𝑦 𝑢 𝑛 1 + 𝑟 𝑦 𝑢 𝑛 , 𝑢 𝑛 𝑥 𝑛 𝐹 𝑦 , 𝑢 𝑛 , 𝑦 𝐶 . ( 3 . 4 5 ) Hence, 𝑢 𝜑 ( 𝑦 ) 𝜑 𝑛 𝑖 + Φ 𝑥 𝑛 𝑖 , 𝑦 𝑢 𝑛 𝑖 + 1 𝑟 𝑦 𝑢 𝑛 𝑖 , 𝑢 𝑛 𝑖 𝑥 𝑛 𝑖 𝐹 𝑦 , 𝑢 𝑛 𝑖 , 𝑦 𝐶 . ( 3 . 4 6 ) For 𝑡 ( 0 , 1 ] and 𝑦 𝐻 , let 𝑦 𝑡 = 𝑡 𝑦 + ( 1 𝑡 ) 𝑤 . From (3.46) we have 𝑦 𝑡 𝑢 𝑛 𝑖 , Φ 𝑦 𝑡 𝑦 𝑡 𝑢 𝑛 𝑖 , Φ 𝑦 𝑡 𝑦 𝜑 𝑡 𝑢 + 𝜑 𝑛 𝑖 Φ 𝑥 𝑛 𝑖 , 𝑦 𝑡 𝑢 𝑛 𝑖 1 𝑟 𝑦 𝑡 𝑢 𝑛 𝑖 , 𝑢 𝑛 𝑖 𝑥 𝑛 𝑖 𝑦 + 𝐹 𝑡 , 𝑢 𝑛 𝑖 = 𝑦 𝑡 𝑢 𝑛 𝑖 , Φ 𝑦 𝑡 Φ 𝑢 𝑛 𝑖 + 𝑦 𝑡 𝑢 𝑛 𝑖 , Φ 𝑢 𝑛 𝑖 Φ 𝑥 𝑛 𝑖 𝑦 𝜑 𝑡 𝑢 + 𝜑 𝑛 𝑖 1 𝑟 𝑦 𝑡 𝑢 𝑛 𝑖 , 𝑢 𝑛 𝑖 𝑥 𝑛 𝑖 𝑦 + 𝐹 𝑡 , 𝑢 𝑛 𝑖 . ( 3 . 4 7 ) From 𝑢 𝑛 𝑖 𝑥 𝑛 𝑖 0 , we have Φ 𝑢 𝑛 𝑖 Φ 𝑥 𝑛 𝑖 0 . Further, from (A4) and the weakly lower semicontinuity of 𝜑 , ( 𝑢 𝑛 𝑖 𝑥 𝑛 𝑖 ) / 𝑟 0 and 𝑢 𝑛 𝑖 𝑤 , we have 𝑦 𝑡 𝑤 , Φ 𝑦 𝑡 𝑦 𝜑 𝑡 𝑦 + 𝜑 ( 𝑤 ) + 𝐹 𝑡 , 𝑤 . ( 3 . 4 8 ) From (A1), (A4), and (3.48), we have 𝑦 0 = 𝐹 𝑡 , 𝑦 𝑡 𝑦 𝜑 𝑡 𝑦 + 𝜑 𝑡 𝑦 𝑡 𝐹 𝑡 𝑦 , 𝑦 + ( 1 𝑡 ) 𝐹 𝑡 𝑦 , 𝑤 + 𝑡 𝜑 ( 𝑦 ) + ( 1 𝑡 ) 𝜑 ( 𝑤 ) 𝜑 𝑡 𝐹 𝑦 = 𝑡 𝑡 𝑦 , 𝑦 + 𝜑 ( 𝑦 ) 𝜑 𝑡 + 𝐹 𝑦 ( 1 𝑡 ) 𝑡 𝑦 , 𝑤 + 𝜑 ( 𝑤 ) 𝜑 𝑡 𝐹 𝑦 𝑡 𝑡 𝑦 , 𝑦 + 𝜑 ( 𝑦 ) 𝜑 𝑡 + ( 1 𝑡 ) 𝑦 𝑡 𝑤 , Φ 𝑦 𝑡 𝐹 𝑦 = 𝑡 𝑡 𝑦 , 𝑦 + 𝜑 ( 𝑦 ) 𝜑 𝑡 + ( 1 𝑡 ) 𝑡 𝑦 𝑤 , Φ 𝑦 𝑡 , ( 3 . 4 9 ) and hence 𝑦 0 𝐹 𝑡 𝑦 , 𝑦 + 𝜑 ( 𝑦 ) 𝜑 𝑡 + ( 1 𝑡 ) 𝑦 𝑤 , Φ 𝑦 𝑡 . ( 3 . 5 0 ) Letting 𝑡 0 , we have, for each 𝑦 𝐶 , 𝐹 ( 𝑤 , 𝑦 ) + 𝜑 ( 𝑦 ) 𝜑 ( 𝑤 ) + 𝑦 𝑤 , Φ 𝑤 0 . ( 3 . 5 1 ) This implies that 𝑤 G M E P ( 𝐹 , 𝜑 , Φ ) .
Lastly, we show that 𝑤 𝐼 ( 𝐵 , 𝑀 ) . In fact, since 𝐵 is a 𝛽 -inverse-strongly monotone, 𝐵 is monotone and Lipschitz continuous mapping. It follows from Lemma 2.3, that 𝑀 + 𝐵 is a maximal monotone. Let ( 𝑣 , 𝑔 ) 𝐺 ( 𝑀 + 𝐵 ) , since 𝑔 𝐵 𝑣 𝑀 ( 𝑣 ) . Again since 𝑦 𝑛 𝑖 = 𝐽 𝑀 , 𝜆 ( 𝑥 𝑛 𝑖 𝜆 𝐵 𝑥 𝑛 𝑖 ) , we have 𝑥 𝑛 𝑖 𝜆 𝐵 𝑥 𝑛 𝑖 ( 𝐼 + 𝜆 𝑀 ) ( 𝑦 𝑛 𝑖 ) , that is, ( 1 / 𝜆 ) ( 𝑥 𝑛 𝑖 𝑦 𝑛 𝑖 𝜆 𝐵 𝑥 𝑛 𝑖 ) 𝑀 ( 𝑦 𝑛 𝑖 ) . By virtue of the maximal monotonicity of 𝑀 + 𝐵 , we have 𝑣 𝑦 𝑛 𝑖 1 , 𝑔 𝐵 𝑣 𝜆 𝑥 𝑛 𝑖 𝑦 𝑛 𝑖 𝜆 𝐵 𝑥 𝑛 𝑖 0 , ( 3 . 5 2 ) and hence 𝑣 𝑦 𝑛 𝑖 , 𝑔 𝑣 𝑦 𝑛 𝑖 1 , 𝐵 𝑣 + 𝜆 𝑥 𝑛 𝑖 𝑦 𝑛 𝑖 𝜆 𝐵 𝑥 𝑛 𝑖 = 𝑣 𝑦 𝑛 𝑖 , 𝐵 𝑣 𝐵 𝑦 𝑛 𝑖 + 𝑣 𝑦 𝑛 𝑖 , 𝐵 𝑦 𝑛 𝑖 𝐵 𝑥 𝑛 𝑖 + 𝑣 𝑦 𝑛 𝑖 , 1 𝜆 𝑥 𝑛 𝑖 𝑦 𝑛 𝑖 . ( 3 . 5 3 ) It follows from l i m 𝑛 𝑥 𝑛 𝑦 𝑛 = 0 , we have l i m 𝑛 𝐵 𝑥 𝑛 𝐵 𝑦 𝑛 = 0 and 𝑦 𝑛 𝑖 𝑤 that l i m s u p 𝑛 𝑣 𝑦 𝑛 , 𝑔 = 𝑣 𝑤 , 𝑔 0 . ( 3 . 5 4 ) It follows from the maximal monotonicity of 𝐵 + 𝑀 that 𝜃 ( 𝑀 + 𝐵 ) ( 𝑤 ) , that is, 𝑤 𝐼 ( 𝐵 , 𝑀 ) . Therefore, 𝑤 Θ . It follows that l i m s u p 𝑛 ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑆 𝑦 𝑛 𝑞 = l i m 𝑘 ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑆 𝑦 𝑛 𝑖 𝑞 = ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑤 𝑞 0 . ( 3 . 5 5 )
Step 6. We prove 𝑥 𝑛 𝑞 . By using (3.2) and together with Schwarz inequality, we have 𝑥 𝑛 + 1 𝑞 2 = 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 + 𝑞 1 𝜉 𝑛 𝑢 𝑛 𝑞 2 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝑃 𝐶 ( 𝑞 ) 2 + 1 𝜉 𝑛 𝑢 𝑛 𝑞 2 𝜉 𝑛 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐴 𝑞 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝑞 2 + 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝜉 𝑛 𝐼 𝛼 𝑛 𝐴 2 𝑆 𝑦 𝑛 𝑞 2 + 𝜉 𝑛 𝛼 2 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 𝐼 𝛼 𝑛 𝐴 𝑆 𝑦 𝑛 𝑥 𝑞 , 𝛾 𝑓 𝑛 + 𝐴 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝜉 𝑛 1 𝛼 𝑛 𝛾 2 𝑦 𝑛 𝑞 2 + 𝜉 𝑛 𝛼 2 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑥 𝑞 , 𝛾 𝑓 𝑛 𝐴 𝑞 2 𝜉 𝑛 𝛼 2 𝑛 𝐴 𝑆 𝑦 𝑛 𝑥 𝑞 , 𝛾 𝑓 𝑛 + 𝐴 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 = 𝜉 𝑛 1 𝛼 𝑛 𝛾 2 𝑥 𝑛 𝑞 2 + 𝜉 𝑛 𝛼 2 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑥 𝑞 , 𝛾 𝑓 𝑛 𝛾 𝑓 ( 𝑞 ) + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑞 , 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 2 𝜉 𝑛 𝛼 2 𝑛 𝐴 𝑆 𝑦 𝑛 𝑥 𝑞 , 𝛾 𝑓 𝑛 + 𝐴 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝜉 𝑛 1 𝛼 𝑛 𝛾 2 𝑥 𝑛 𝑞 2 + 𝜉 𝑛 𝛼 2 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑥 𝑞 𝛾 𝑓 𝑛 𝛾 𝑓 ( 𝑞 ) + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑞 , 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 2 𝜉 𝑛 𝛼 2 𝑛 𝐴 𝑆 𝑦 𝑛 𝑥 𝑞 , 𝛾 𝑓 𝑛 + 𝐴 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝜉 𝑛 1 𝛼 𝑛 𝛾 2 𝑥 𝑛 𝑞 2 + 𝜉 𝑛 𝛼 2 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛾 𝛼 𝛼 𝑛 𝑦 𝑛 𝑥 𝑞 𝑛 𝑞 + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑞 , 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 2 𝜉 𝑛 𝛼 2 𝑛 𝐴 𝑆 𝑦 𝑛 𝑥 𝑞 , 𝛾 𝑓 𝑛 + 𝐴 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 𝜉 𝑛 2 𝜉 𝑛 𝛼 𝑛 𝛾 + 𝜉 𝑛 𝛼 2 𝑛 𝛾 2 𝑥 𝑛 𝑞 2 + 𝜉 𝑛 𝛼 2 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛾 𝛼 𝛼 𝑛 𝑥 𝑛 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑞 , 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 2 𝜉 𝑛 𝛼 2 𝑛 𝐴 𝑆 𝑦 𝑛 𝑥 𝑞 , 𝛾 𝑓 𝑛 + 𝐴 𝑞 1 𝜉 𝑛 𝑥 𝑛 𝑞 2 = 1 2 𝜉 𝑛 𝛼 𝑛 𝛾 + 2 𝜉 𝑛 𝛾 𝛼 𝛼 𝑛 𝑥 𝑛 𝑞 2 + 𝜉 𝑛 𝛼 2 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑞 , 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 2 𝜉 𝑛 𝛼 2 𝑛 𝐴 𝑆 𝑦 𝑛 𝑥 𝑞 𝛾 𝑓 𝑛 𝐴 𝑞 + 𝜉 𝑛 𝛼 2 𝑛 𝛾 2 𝑥 𝑛 𝑞 2 = 1 2 𝜉 𝛾 𝛾 𝛼 𝑛 𝛼 𝑛 𝑥 𝑛 𝑞 2 + 𝜉 𝑛 𝛼 2 𝑛 𝑥 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 2 𝜉 𝑛 𝛼 𝑛 𝑆 𝑦 𝑛 𝑞 , 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 2 𝜉 𝑛 𝛼 2 𝑛 𝐴 𝑆 𝑦 𝑛 𝑥 𝑞 𝛾 𝑓 𝑛 𝐴 𝑞 + 𝜉 𝑛 𝛼 2 𝑛 𝛾 2 𝑥 𝑛 𝑞 2 = 1 2 𝜉 𝛾 𝛾 𝛼 𝑛 𝛼 𝑛 𝑥 𝑛 𝑞 2 + 2 𝜉 𝛾 𝛾 𝛼 𝑛 𝛼 𝑛 𝛼 𝑛 2 𝑥 𝛾 𝛾 𝛼 𝛾 𝑓 𝑛 𝐴 𝑞 2 + 1 𝛾 𝛾 𝛼 𝑆 𝑦 𝑛 𝛼 𝑞 , 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 𝑛 𝐴 𝛾 𝛾 𝛼 𝑆 𝑦 𝑛 𝑥 𝑞 𝛾 𝑓 𝑛 + 𝛼 𝐴 𝑞 𝑛 𝛾 2 2 𝑥 𝛾 𝛾 𝛼 𝑛 𝑞 2 = 1 𝛾 𝑛 𝑥 𝑛 𝑞 2 + 𝛾 𝑛 𝛿 𝑛 , ( 3 . 5 6 ) where 𝛾 𝑛 = 2 ( 𝛾 𝛾 𝛼 ) and 𝛿 𝑛 = ( 𝛼 𝑛 / 2 ( 𝛾 𝛾 𝛼 ) ) 𝛾 𝑓 ( 𝑥 𝑛 ) 𝐴 𝑞 2 + ( 1 / ( 𝛾 𝛾 𝛼 ) ) 𝑆 𝑦 𝑛 𝑞 , 𝛾 𝑓 ( 𝑞 ) 𝐴 𝑞 ( 𝛼 𝑛 / ( 𝛾 𝛾 𝛼 ) ) 𝐴 ( 𝑆 𝑦 𝑛 𝑞 ) 𝛾 𝑓 ( 𝑥 𝑛 ) 𝐴 𝑞 + ( 𝛼 𝑛 𝛾 2 / 2 ( 𝛾 𝛾 𝛼 ) ) 𝑥 𝑛 𝑞 2 . It is clear that 𝑛 = 0 𝛾 𝑛 = and l i m s u p 𝑛 𝛿 𝑛 0 . Hence, all conditions of Lemma 2.5, we can conclude that 𝑥 𝑛 𝑞 . This completes the proof.

Corollary 3.2. Let 𝐻 be a real Hilbert space and 𝐶 be a closed convex subset of 𝐻 . Let 𝐹 be a bifunction of 𝐶 × 𝐶 into satisfying (A1)–(A4) and 𝐵 , Φ 𝐶 𝐻 be 𝛽 , 𝜎 -inverse-strongly monotone mappings, let 𝜑 𝐶 be convex and lower semicontinuous function, 𝑓 𝐶 𝐶 be a contraction with coefficient 𝛼 ( 0 < 𝛼 < 1 ) , and 𝑀 𝐻 2 𝐻 be a maximal monotone mapping. Let 𝑆 be a nonexpansive mapping of 𝐻 into itself and assume that either (B1) or (B2) holds such that Θ = 𝐹 ( 𝑆 ) G M E P ( 𝐹 , 𝜑 , Φ ) 𝐼 ( 𝐵 , 𝑀 ) . ( 3 . 5 7 ) Suppose { 𝑥 𝑛 } is a sequence generated by the following algorithm 𝑥 0 𝐶 arbitrarily: 𝑥 𝑛 + 1 = 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑓 𝑥 𝑛 + 𝐼 𝛼 𝑛 𝑆 𝐽 𝑀 , 𝜆 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 + 1 𝜉 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 , ( 3 . 5 8 ) where { 𝛼 𝑛 } , { 𝜉 𝑛 } ( 0 , 1 ) , 𝜆 ( 0 , 2 𝛽 ) such that 0 < 𝑎 𝜆 𝑏 < 2 𝛽 and 𝑟 ( 0 , 2 𝜎 ) with 0 < 𝑐 𝑑 1 𝜎 satisfy the following conditions: (C1) l i m 𝑛 𝛼 𝑛 = 0 , Σ 𝑛 = 0 𝛼 𝑛 = and l i m 𝑛 ( 𝛼 𝑛 + 1 / 𝛼 𝑛 ) = 1 ,(C2) 0 < l i m i n f 𝑛 𝜉 𝑛 < l i m s u p 𝑛 𝜉 𝑛 < 1 and l i m 𝑛 ( ( 𝜉 𝑛 + 1 𝜉 𝑛 ) / 𝛼 𝑛 + 1 ) = 1 .
Then { 𝑥 𝑛 } converges strongly to 𝑞 Θ , where 𝑞 = 𝑃 Θ ( 𝑓 + 𝐼 ) ( 𝑞 ) which solves the following variational inequality: ( 𝑓 𝐼 ) 𝑞 , 𝑝 𝑞 0 , 𝑝 Θ . ( 3 . 5 9 )

Proof. Putting 𝐴 𝐼 and 𝛾 1 in Theorem 3.1, we can obtain desired conclusion immediately.

Corollary 3.3. Let 𝐻 be a real Hilbert space and 𝐶 be a closed convex subset of 𝐻 . Let 𝐹 be a bifunction of 𝐶 × 𝐶 into satisfying (A1)–(A4) and 𝐵 , Φ 𝐶 𝐻 be 𝛽 , 𝜎 -inverse-strongly monotone mappings, let 𝜑 𝐶 be convex and lower semicontinuous function, and 𝑀 𝐻 2 𝐻 be a maximal monotone mapping. Let 𝑆 be a nonexpansive mapping of 𝐻 into itself and assume that either (B1) or (B2) holds such that Θ = 𝐹 ( 𝑆 ) G M E P ( 𝐹 , 𝜑 , Φ ) 𝐼 ( 𝐵 , 𝑀 ) . ( 3 . 6 0 ) Suppose { 𝑥 𝑛 } is a sequence generated by the following algorithm 𝑥 0 𝐶 arbitrarily: 𝑥 𝑛 + 1 = 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑢 + 𝐼 𝛼 𝑛 𝑆 𝐽 𝑀 , 𝜆 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 + 1 𝜉 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 , ( 3 . 6 1 ) where { 𝛼 𝑛 } , { 𝜉 𝑛 } ( 0 , 1 ) , 𝜆 ( 0 , 2 𝛽 ) such that 0 < 𝑎 𝜆 𝑏 < 2 𝛽 and 𝑟 ( 0 , 2 𝜎 ) with 0 < 𝑐 𝑑 1 𝜎 satisfy the following conditions: (C1) l i m 𝑛 𝛼 𝑛 = 0 , Σ 𝑛 = 0 𝛼 𝑛 = and l i m 𝑛 ( 𝛼 𝑛 + 1 / 𝛼 𝑛 ) = 1 ,(C2) 0 < l i m i n f 𝑛 𝜉 𝑛 < l i m s u p 𝑛 𝜉 𝑛 < 1 and l i m 𝑛 ( ( 𝜉 𝑛 + 1 𝜉 𝑛 ) / 𝛼 𝑛 + 1 ) = 1 .Then { 𝑥 𝑛 } converges strongly to 𝑞 Θ , where 𝑞 = 𝑃 Θ ( 𝑞 ) which solves the following variational inequality: 𝑢 𝑞 , 𝑝 𝑞 0 , 𝑝 Θ . ( 3 . 6 2 )

Proof. Putting 𝑓 𝑢 𝐶 in Corollary 3.2, we can obtain desired conclusion immediately.

Corollary 3.4. Let 𝐻 be a real Hilbert space, 𝐶 be a closed convex subset of H . Let 𝐹 be a bifunction of 𝐶 × 𝐶 into satisfying (A1)–(A4) and 𝐵 , Φ 𝐶 𝐻 be 𝛽 , 𝜎 -inverse-strongly monotone mappings, 𝜑 𝐶 is convex and lower semicontinuous function, 𝑓 𝐶 𝐶 be a contraction with coefficient 𝛼 ( 0 < 𝛼 < 1 ) and 𝐴 be a strongly positive linear bounded operator of 𝐻 into itself with coefficient 𝛾 > 0 . Assume that 0 < 𝛾 < 𝛾 / 𝛼 . Let 𝑆 be a nonexpansive mapping of 𝐶 into itself and assume that either (B1) or (B2) holds such that Θ = 𝐹 ( 𝑆 ) G M E P ( 𝐹 , 𝜑 , Φ ) V I ( 𝐶 , 𝐵 ) . ( 3 . 6 3 ) Suppose { 𝑥 𝑛 } is a sequence generated by the following algorithm 𝑥 0 𝐶 arbitrarily: 𝑥 𝑛 + 1 = 𝜉 𝑛 𝑃 𝐶 𝛼 n 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 𝑃 𝐶 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 + 1 𝜉 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 , ( 3 . 6 4 ) where { 𝛼 𝑛 } , { 𝜉 𝑛 } ( 0 , 1 ) , 𝜆 ( 0 , 2 𝛽 ) such that 0 < 𝑎 𝜆 𝑏 < 2 𝛽 and 𝑟 ( 0 , 2 𝜎 ) with 0 < 𝑐 𝑑 1 𝜎 satisfing the following conditions: (C1) l i m 𝑛 𝛼 𝑛 = 0 , Σ 𝑛 = 0 𝛼 𝑛 = and l i m 𝑛 ( 𝛼 𝑛 + 1 / 𝛼 𝑛 ) = 1 ,(C2) 0 < l i m i n f 𝑛 𝜉 𝑛 < l i m s u p n 𝜉 𝑛 < 1 and l i m 𝑛 ( ( 𝜉 𝑛 + 1 𝜉 𝑛 ) / 𝛼 𝑛 + 1 ) = 1 .
Then { 𝑥 𝑛 } converges strongly to 𝑞 Θ , where 𝑞 = 𝑃 Θ ( 𝛾 𝑓 + 𝐼 𝐴 ) ( 𝑞 ) which solves the following variational inequality: ( 𝛾 𝑓 ) 𝑞 , 𝑝 𝑞 0 , 𝑝 Θ . ( 3 . 6 5 )

Proof. Taking 𝐽 𝑀 , 𝜆 = 𝑃 𝐶 in Theorem 3.1, we can obtain desired conclusion immediately.

Corollary 3.5. Let 𝐻 be a real Hilbert space, 𝐶 be a closed convex subset of 𝐻 . Let 𝐹 be a bifunction of 𝐶 × 𝐶 into satisfying (A1)–(A4) and 𝐵 , Φ 𝐶 𝐻 be 𝛽 , 𝜎 -inverse-strongly monotone mappings, 𝜑 𝐶 is convex and lower semicontinuous function, 𝑓 𝐶 𝐶 be a contraction with coefficient 𝛼 ( 0 < 𝛼 < 1 ) . Let 𝑆 be a nonexpansive mapping of 𝐶 into itself and assume that either (B1) or (B2) holds such that Θ = 𝐹 ( 𝑆 ) G M E P ( 𝐹 , 𝜑 , Φ ) . ( 3 . 6 6 ) Suppose { 𝑥 𝑛 } is a sequence generated by the following algorithm 𝑥 0 𝐶 arbitrarily: 𝑥 𝑛 + 1 = 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑓 𝑥 𝑛 + 𝐼 𝛼 𝑛 𝑆 𝑥 𝑛 + 1 𝜉 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 , ( 3 . 6 7 ) where { 𝛼 𝑛 } , { 𝜉 𝑛 } ( 0 , 1 ) and 𝑟 ( 0 , 2 𝜎 ) with 0 < 𝑐 𝑑 1 𝜎 satisfing the following conditions: (C1) l i m 𝑛 𝛼 𝑛 = 0 , Σ 𝑛 = 0 𝛼 𝑛 = and l i m 𝑛 ( 𝛼 𝑛 + 1 / 𝛼 𝑛 ) = 1 ,(C2) 0 < l i m i n f 𝑛 𝜉 𝑛 < l i m s u p 𝑛 𝜉 𝑛 < 1 and l i m 𝑛 ( ( 𝜉 𝑛 + 1 𝜉 𝑛 ) / 𝛼 𝑛 + 1 ) = 1 .
Then { 𝑥 𝑛 } converges strongly to 𝑞 Θ , where 𝑞 = 𝑃 Θ ( 𝑓 + 𝐼 ) ( 𝑞 ) which solves the following variational inequality: ( 𝑓 𝐼 ) 𝑞 , 𝑝 𝑞 0 , 𝑝 Θ . ( 3 . 6 8 )

Proof. Taking 𝛾 1 , 𝐴 𝐼 , 𝑀 = 0 , and 𝐵 0 in Theorem 3.1, we can obtain desired conclusion immediately.

Remark 3.6. Corollary 3.5 generalizes and improves the result of Yao and Liou [16].

4. Some Applications

In this section, we apply the iterative scheme (1.22) for finding a common fixed point of nonexpansive mapping and strictly pseudocontractive mapping and also apply Theorem 3.1 for finding a common fixed point of nonexpansive mappings and inverse-strongly monotone mappings.

Definition 4.1. A mapping 𝑇 𝐶 𝐶 is called strictly pseudocontraction if there exists a constant 0 𝜅 < 1 such that 𝑇 𝑥 𝑇 𝑦 2 𝑥 𝑦 2 + 𝜅 ( 𝐼 𝑇 ) 𝑥 ( 𝐼 𝑇 ) 𝑦 2 , 𝑥 , 𝑦 𝐶 . ( 4 . 1 ) If 𝜅 = 0 , then 𝑆 is nonexpansive. In this case, we say that 𝑇 𝐶 𝐶 is a 𝜅 -strictly pseudocontraction. Putting 𝐵 = 𝐼 𝑇 . Then, we have ( 𝐼 𝐵 ) 𝑥 ( 𝐼 𝐵 ) 𝑦 2 𝑥 𝑦 2 + 𝜅 𝐵 𝑥 𝐵 𝑦 2 , 𝑥 , 𝑦 𝐶 . ( 4 . 2 ) Observe that ( 𝐼 𝐵 ) 𝑥 ( 𝐼 𝐵 ) 𝑦 2 = 𝑥 𝑦 2 + 𝐵 𝑥 𝐵 𝑦 2 2 𝑥 𝑦 , 𝐵 𝑥 𝐵 𝑦 , 𝑥 , 𝑦 𝐶 . ( 4 . 3 ) Hence, we obtain 𝑥 𝑦 , 𝐵 𝑥 𝐵 𝑦 1 𝜅 2 𝐵 𝑥 𝐵 𝑦 2 , 𝑥 , 𝑦 𝐶 . ( 4 . 4 ) Then, 𝐵 is ( ( 1 𝜅 ) / 2 ) -inverse-strongly monotone mapping.

Using Theorem 3.1, we first prove a strongly convergence theorem for finding a common fixed point of a nonexpansive mapping and a strictly pseudocontraction.

Theorem 4.2. Let 𝐻 be a real Hilbert space and 𝐶 be a closed convex subset of 𝐻 . Let 𝐹 be a bifunction of 𝐶 × 𝐶 into satisfying (A1)–(A4) and 𝐵 , Φ 𝐶 𝐻 be 𝛽 , 𝜎 -inverse-strongly monotone mapping, 𝜑 𝐶 be convex and lower semicontinuous function, 𝑓 𝐶 𝐶 be a contraction with coefficient 𝛼 ( 0 < 𝛼 < 1 ) , and 𝐴 be a strongly positive linear bounded operator of 𝐻 into itself with coefficient 𝛾 > 0 . Assume that 0 < 𝛾 < 𝛾 / 𝛼 . Let 𝑆 be a nonexpansive mapping of 𝐶 into itself and let 𝑇 be a 𝜅 -strictly pseudocontraction of 𝐶 into itself. Assume that either (B1) or (B2) holds such that Θ = 𝐹 ( 𝑆 ) 𝐹 ( 𝑇 ) G M E P ( 𝐹 , 𝜑 , Φ ) . ( 4 . 5 ) Suppose { 𝑥 𝑛 } is a sequence generated by the following algorithm 𝑥 0 𝐶 arbitrarily: 𝑥 𝑛 + 1 = 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑥 𝛾 𝑓 𝑛 + 𝐼 𝛼 𝑛 𝐴 𝑆 ( 1 𝜆 ) 𝑢 𝑛 + 𝜆 𝑇 𝑢 𝑛 + 1 𝜉 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 , ( 4 . 6 ) for all 𝑛 = 0 , 1 , 2 , , where { 𝛼 𝑛 } , { 𝜉 𝑛 } ( 0 , 1 ) , 𝜆 [ 0 , 1 𝜅 ) and 𝑟 ( 0 , 2 𝜎 ) . If 𝜆 [ 𝑎 , 𝑏 ] for some 𝑎 , 𝑏 with 0 < 𝑎 < 𝑏 < 1 𝜅 and { 𝜎 𝑛 } is chosen so that 𝑟 [ 𝑐 , 𝑑 ] for some 𝑐 , 𝑑 with 0 < 𝑐 < 𝑑 < 1 𝜎 and satisfy the condition (C1)-(C2) in Theorem 3.1.
Then { 𝑥 𝑛 } converges strongly to 𝑞 Θ , where 𝑞 = 𝑃 Θ ( 𝛾 𝑓 + 𝐼 𝐴 ) ( 𝑞 ) which solves the following variational inequality: ( 𝛾 𝑓 𝐴 ) 𝑞 , 𝑝 𝑞 0 , p Θ , ( 4 . 7 ) which is the optimality condition for the minimization problem m i n 𝑞 Ω 1 2 𝐴 𝑞 , 𝑞 ( 𝑞 ) , ( 4 . 8 ) where is a potential function for 𝛾 𝑓 (i.e., ( 𝑞 ) = 𝛾 𝑓 ( 𝑞 ) for 𝑞 𝐻 ).

Proof. Put 𝐵 𝐼 𝑇 , then 𝐵 is ( ( 1 𝜅 ) / 2 ) -inverse-strongly monotone and 𝐹 ( 𝑇 ) = 𝐼 ( 𝐵 , 𝑀 ) and 𝐽 𝑀 , 𝜆 ( 𝑥 𝑛 𝜆 𝐵 𝑥 𝑛 ) = ( 1 𝜆 ) 𝑥 𝑛 + 𝜆 𝑇 𝑥 𝑛 . So by Theorem 3.1, we obtain the desired result.

Corollary 4.3. Let 𝐻 be a real Hilbert space and 𝐶 be a closed convex subset of 𝐻 . Let 𝐹 be a bifunction of 𝐶 × 𝐶 into satisfying (A1)–(A4) and 𝐵 , Φ 𝐶 𝐻 be 𝛽 , 𝜎 -inverse-strongly monotone mapping, 𝜑 𝐶 is convex and lower semicontinuous function. Let 𝑓 𝐶 𝐶 be a contraction with coefficient 𝛼 ( 0 < 𝛼 < 1 ) and 𝑆 be a nonexpansive mapping of 𝐶 into itself and let 𝑇 be a 𝜅 -strictly pseudocontraction of 𝐶 into itself. Assume that either (B1) or (B2) holds such that Θ = 𝐹 ( 𝑆 ) 𝐹 ( 𝑇 ) G M E P ( 𝐹 , 𝜑 , Φ ) . ( 4 . 9 ) Suppose { 𝑥 𝑛 } is a sequence generated by the following algorithm 𝑥 0 𝐶 arbitrarily: 𝑥 𝑛 + 1 = 𝜉 𝑛 𝑃 𝐶 𝛼 𝑛 𝑓 𝑥 𝑛 + 𝐼 𝛼 𝑛 𝑆 ( 1 𝜆 ) 𝑢 𝑛 + 𝜆 𝑇 𝑢 𝑛 + 1 𝜉 𝑛 𝑇 𝑟 𝑥 𝑛 𝑟 Φ 𝑥 𝑛 , ( 4 . 1 0 ) for all 𝑛 = 0 , 1 , 2 , , where { 𝛼 𝑛 } , { 𝜉 𝑛 } ( 0 , 1 ) , 𝜆 [ 0 , 1 𝜅 ) and 𝑟 ( 0 , 2 𝜎 ) . If 𝜆 [ 𝑎 , 𝑏 ] is chosen for some 𝑎 , 𝑏 with 0 < 𝑎 < 𝑏 < 1 𝜅 and { 𝜎 𝑛 } is chosen so that 𝑟 [ 𝑐 , 𝑑 ] for some 𝑐 , 𝑑 with 0 < 𝑐 < 𝑑 < 1 𝜎 and satisfy the condition (C1)-(C2) in Theorem 3.1.

Then { 𝑥 𝑛 } converges strongly to 𝑞 Ω , where 𝑞 = 𝑃 Ω ( 𝑓 + 𝐼 ) ( 𝑞 ) which solves the following variational inequality: ( 𝑓 𝐼 ) 𝑞 , 𝑝 𝑞 , 𝑝 Ω . ( 4 . 1 1 )

Proof. Put 𝐴 𝐼 and 𝛾 1 in by Theorem 4.2, we obtain the desired result.

Acknowledgments

The authors would like to express their thanks to the referees for their helpful comments and suggestions. The authers would like to thank the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission for financial support under the Computational Science and Engineering Research Cluster (CSEC) Grant no.54000267. Moreover, the second author was supported by the Commission on Higher Education and the Thailand Research Fund under Grant MRG5380044.

References

  1. E. Blum and W. Oettli, “From optimization and variational inequalities to equilibrium problems,” The Mathematics Student, vol. 63, no. 1-4, pp. 123–145, 1994. View at Zentralblatt MATH
  2. P. L. Combettes and S. A. Hirstoaga, “Equilibrium programming in Hilbert spaces,” Journal of Nonlinear and Convex Analysis, vol. 6, no. 1, pp. 117–136, 2005. View at Zentralblatt MATH
  3. S. D. Flåm and A. S. Antipin, “Equilibrium programming using proximal-like algorithms,” Mathematical Programming, vol. 78, no. 1, pp. 29–41, 1997. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  4. S. Takahashi and W. Takahashi, “Viscosity approximation methods for equilibrium problems and fixed point problems in Hilbert spaces,” Journal of Mathematical Analysis and Applications, vol. 331, no. 1, pp. 506–515, 2007. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  5. P. Hartman and G. Stampacchia, “On some non-linear elliptic differential-functional equations,” Acta Mathematica, vol. 115, pp. 271–310, 1966. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  6. J.-C. Yao and O. Chadli, “Pseudomonotone complementarity problems and variational inequalities,” in Handbook of Generalized Convexity and Generalized Monotonicity, J. P. Crouzeix, N. Haddjissas, and S. Schaible, Eds., vol. 76 of Nonconvex Optim. Appl., pp. 501–558, Springer, New York, NY, USA, 2005. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  7. G. Marino and H.-K. Xu, “A general iterative method for nonexpansive mappings in Hilbert spaces,” Journal of Mathematical Analysis and Applications, vol. 318, no. 1, pp. 43–52, 2006. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  8. W. A. Kirk, “A fixed point theorem for mappings which do not increase distances,” The American Mathematical Monthly, vol. 72, pp. 1004–1006, 1965. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  9. Y. Hao, “Some results of variational inclusion problems and fixed point problems with applications,” Applied Mathematics and Mechanics. English Edition, vol. 30, no. 12, pp. 1589–1596, 2009. View at Publisher · View at Google Scholar · View at Zentralblatt MATH
  10. M. Liu, S. S. Chang, and P. Zuo, “An algorithm for finding a common solution for a system of mixed equilibrium problem, quasivariational inclusion problem, and fixed point problem of nonexpansive semigroup,” Journal of Inequalities and Applications, vol. 2010, Article ID 895907, 23 pages, 2010. View at Publisher · View at Google Scholar · View at Zentralblatt MATH
  11. J. F. Tan and S. S. Chang, “Iterative algorithms for finding common solutions to variational inclusion equilibrium and fixed point problems,” Fixed Point Theory and Applications, vol. 2011, Article ID 915629, 17 pages, 2011. View at Publisher · View at Google Scholar · View at Zentralblatt MATH
  12. S.-S. Zhang, J. H. W. Lee, and C. K. Chan, “Algorithms of common solutions to quasi variational inclusion and fixed point problems,” Applied Mathematics and Mechanics. English Edition, vol. 29, no. 5, pp. 571–581, 2008. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  13. R. T. Rockafellar, “On the maximality of sums of nonlinear monotone operators,” Transactions of the American Mathematical Society, vol. 149, pp. 75–88, 1970. View at Publisher · View at Google Scholar · View at Zentralblatt MATH
  14. W. Takahashi, Nonlinear Functional Analysis: Fixed Point Theory and Its Applications, Yokohama Publishers, Yokohama, Japan, 2000.
  15. A. Moudafi, “Viscosity approximation methods for fixed-points problems,” Journal of Mathematical Analysis and Applications, vol. 241, no. 1, pp. 46–55, 2000. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  16. Y. Yao and Y.-C. Liou, “Composite algorithms for minimization over the solutions of equilibrium problems and fixed point problems,” Abstract and Applied Analysis, vol. 2010, Article ID 763506, 19 pages, 2010. View at Publisher · View at Google Scholar · View at Zentralblatt MATH
  17. H. Brézis, “Opérateur maximaux monotones,” in Mathematics Studies, vol. 5, North-Holland, Amsterdam, The Netherlands, 1973.
  18. Z. Opial, “Weak convergence of the sequence of successive approximations for nonexpansive mappings,” Bulletin of the American Mathematical Society, vol. 73, pp. 591–597, 1967. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  19. H. K. Xu, “An iterative approach to quadratic optimization,” Journal of Optimization Theory and Applications, vol. 116, no. 3, pp. 659–678, 2003. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet
  20. F. E. Browder, “Nonlinear operators and nonlinear equations of evolution in Banach spaces,” in Nonlinear Functional Analysis (Proc. Sympos. Pure Math., Vol. XVIII, Part 2, Chicago, Ill., 1968), pp. 1–308, Amer. Math. Soc., Providence, RI, USA, 1976. View at Zentralblatt MATH
  21. J.-W. Peng, Y.-C. Liou, and J.-C. Yao, “An iterative algorithm combining viscosity method with parallel method for a generalized equilibrium problem and strict pseudocontractions,” Fixed Point Theory and Applications, vol. 2009, Article ID 794178, 21 pages, 2009. View at Publisher · View at Google Scholar · View at Zentralblatt MATH