research article strong convergence for hybrid s-iteration...

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Hindawi Publishing Corporation Journal of Applied Mathematics Volume 2013, Article ID 705814, 4 pages http://dx.doi.org/10.1155/2013/705814 Research Article Strong Convergence for Hybrid S-Iteration Scheme Shin Min Kang, 1 Arif Rafiq, 2 and Young Chel Kwun 3 1 Department of Mathematics and RINS, Gyeongsang National University, Jinju 660-701, Republic of Korea 2 School of CS and Mathematics, Hajvery University, 43-52 Industrial Area, Gulberg-III, Lahore 54660, Pakistan 3 Department of Mathematics, Dong-A University, Pusan 614-714, Republic of Korea Correspondence should be addressed to Young Chel Kwun; [email protected] Received 19 November 2012; Accepted 4 February 2013 Academic Editor: D. R. Sahu Copyright © 2013 Shin Min Kang et al. is 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. We establish a strong convergence for the hybrid S-iterative scheme associated with nonexpansive and Lipschitz strongly pseudo- contractive mappings in real Banach spaces. 1. Introduction and Preliminaries Let be a real Banach space and let be a nonempty convex subset of . Let denote the normalized duality mapping from to 2 defined by () = { : ⟨, ⟩ = ‖‖ 2 , = ‖‖} , ∀, ∈ , (1) where denotes the dual space of and ⟨⋅, ⋅⟩ denotes the generalized duality pairing. We will denote the single-valued duality map by . Let :→ be a mapping. Definition 1. e mapping is said to be Lipschitzian if there exists a constant >1 such that , ∀, ∈ . (2) Definition 2. e mapping is said to be nonexpansive if , ∀, ∈ . (3) Definition 3. e mapping is said to be pseudocontractive if for all , ∈ , there exists ( − ) ∈ ( − ) such that ⟨ − , ( − )⟩ ≤ 2 . (4) Definition 4. e mapping is said to be strongly pseudocon- tractive if for all , ∈ , there exists ∈ (0, 1) such that ⟨ − , ( − )⟩ ≤ 2 . (5) Let be a nonempty convex subset of a normed space . (a) e sequence { } defined by, for arbitrary 1 , +1 = (1 − ) + , = (1 − ) + , ≥ 1, (6) where { } and { } are sequences in [0, 1], is known as the Ishikawa iteration process [1]. If =0 for ≥1, then the Ishikawa iteration process becomes the Mann iteration process [2]. (b) e sequence { } defined by, for arbitrary 1 , +1 = , = (1 − ) + , ≥ 1, (7) where { } is a sequence in [0, 1], is known as the - iteration process [3, 4]. In the last few years or so, numerous papers have been published on the iterative approximation of fixed points of Lipschitz strongly pseudocontractive mappings using the Ishikawa iteration scheme (see, e.g., [1]). Results which had

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Page 1: Research Article Strong Convergence for Hybrid S-Iteration ...downloads.hindawi.com/journals/jam/2013/705814.pdf · : is a continuous strongly pseudocontractive mapping, then the

Hindawi Publishing CorporationJournal of Applied MathematicsVolume 2013 Article ID 705814 4 pageshttpdxdoiorg1011552013705814

Research ArticleStrong Convergence for Hybrid S-Iteration Scheme

Shin Min Kang1 Arif Rafiq2 and Young Chel Kwun3

1 Department of Mathematics and RINS Gyeongsang National University Jinju 660-701 Republic of Korea2 School of CS and Mathematics Hajvery University 43-52 Industrial Area Gulberg-III Lahore 54660 Pakistan3 Department of Mathematics Dong-A University Pusan 614-714 Republic of Korea

Correspondence should be addressed to Young Chel Kwun yckwundauackr

Received 19 November 2012 Accepted 4 February 2013

Academic Editor D R Sahu

Copyright copy 2013 Shin Min Kang et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

We establish a strong convergence for the hybrid S-iterative scheme associated with nonexpansive and Lipschitz strongly pseudo-contractive mappings in real Banach spaces

1 Introduction and Preliminaries

Let 119864 be a real Banach space and let119870 be a nonempty convexsubset of 119864 Let 119869 denote the normalized duality mappingfrom 119864 to 2

119864lowast

defined by

119869 (119909) = 119891lowastisin 119864lowast ⟨119909 119891

lowast⟩ = 119909

2

1003817100381710038171003817119891lowast1003817100381710038171003817 = 119909 forall119909 119910 isin 119864

(1)

where 119864lowast denotes the dual space of 119864 and ⟨sdot sdot⟩ denotes the

generalized duality pairing We will denote the single-valuedduality map by 119895

Let 119879 119870 rarr 119870 be a mapping

Definition 1 Themapping 119879 is said to be Lipschitzian if thereexists a constant 119871 gt 1 such that

1003817100381710038171003817119879119909 minus 1198791199101003817100381710038171003817 le 119871

1003817100381710038171003817119909 minus 1199101003817100381710038171003817 forall119909 119910 isin 119870 (2)

Definition 2 Themapping 119879 is said to be nonexpansive if

1003817100381710038171003817119879119909 minus 1198791199101003817100381710038171003817 le

1003817100381710038171003817119909 minus 1199101003817100381710038171003817 forall119909 119910 isin 119870 (3)

Definition 3 Themapping 119879 is said to be pseudocontractive iffor all 119909 119910 isin 119870 there exists 119895(119909 minus 119910) isin 119869(119909 minus 119910) such that

⟨119879119909 minus 119879119910 119895 (119909 minus 119910)⟩ le1003817100381710038171003817119909 minus 119910

1003817100381710038171003817

2 (4)

Definition 4 Themapping 119879 is said to be strongly pseudocon-tractive if for all 119909 119910 isin 119870 there exists 119896 isin (0 1) such that

⟨119879119909 minus 119879119910 119895 (119909 minus 119910)⟩ le 1198961003817100381710038171003817119909 minus 119910

1003817100381710038171003817

2 (5)

Let 119870 be a nonempty convex subset 119862 of a normed space119864

(a) The sequence 119909119899 defined by for arbitrary 119909

1isin 119870

119909119899+1

= (1 minus 120572119899) 119909119899+ 120572119899119879119910119899

119910119899= (1 minus 120573

119899) 119909119899+ 120573119899119879119909119899 119899 ge 1

(6)

where 120572119899 and 120573

119899 are sequences in [0 1] is known

as the Ishikawa iteration process [1]If 120573119899= 0 for 119899 ge 1 then the Ishikawa iteration process

becomes the Mann iteration process [2](b) The sequence 119909

119899 defined by for arbitrary 119909

1isin 119870

119909119899+1

= 119879119910119899

119910119899= (1 minus 120573

119899) 119909119899+ 120573119899119879119909119899 119899 ge 1

(7)

where 120573119899 is a sequence in [0 1] is known as the 119878-

iteration process [3 4]

In the last few years or so numerous papers have beenpublished on the iterative approximation of fixed pointsof Lipschitz strongly pseudocontractive mappings using theIshikawa iteration scheme (see eg [1]) Results which had

2 Journal of Applied Mathematics

been known only in Hilbert spaces and only for Lipschitzmappings have been extended to more general Banach spaces(see eg [5ndash10] and the references cited therein)

In 1974 Ishikawa [1] proved the following result

Theorem 5 Let 119870 be a compact convex subset of a Hilbertspace 119867 and let 119879 119870 rarr 119870 be a Lipschitzian pseudocon-tractive mapping For arbitrary 119909

1isin 119870 let 119909

119899 be a sequence

defined iteratively by

119909119899+1

= (1 minus 120572119899) 119909119899+ 120572119899119879119910119899

119910119899= (1 minus 120573

119899) 119909119899+ 120573119899119879119909119899 119899 ge 1

(8)

where 120572119899 and 120573

119899 are sequences satisfying

(i) 0 le 120572119899le 120573119899le 1

(ii) lim119899rarrinfin

120573119899= 0

(iii) sum119899ge1

120572119899120573119899= infin

Then the sequence 119909119899 converges strongly at a fixed point of 119879

In [6] Chidume extended the results of Schu [9] fromHilbert spaces to the much more general class of real Banachspaces and approximated the fixed points of (strongly) pseu-docontractive mappings

In [11] Zhou and Jia gave the more general answer of thequestion raised by Chidume [5] and proved the following

If 119883 is a real Banach space with a uniformly convex dual119883lowast119870 is a nonempty bounded closed convex subset of119883 and

119879 119870 rarr 119870 is a continuous strongly pseudocontractivemapping then the Ishikawa iteration scheme convergesstrongly at the unique fixed point of 119879

In this paper we establish the strong convergence forthe hybrid 119878-iterative scheme associated with nonexpansiveand Lipschitz strongly pseudocontractive mappings in realBanach spaces We also improve the result of Zhou and Jia[11]

2 Main Results

We will need the following lemmas

Lemma 6 (see [12]) Let 119869 119864 rarr 2119864 be the normalized

duality mapping Then for any 119909 119910 isin 119864 one has

1003817100381710038171003817119909 + 1199101003817100381710038171003817

2le 119909

2+ 2 ⟨119910 119895 (119909 + 119910)⟩

forall119895 (119909 + 119910) isin 119869 (119909 + 119910)

(9)

Lemma 7 (see [10]) Let 120588119899 be nonnegative sequence satisfy-

ing

120588119899+1

le (1 minus 120579119899) 120588119899+ 120596119899 (10)

where 120579119899isin [0 1]sum

119899ge1120579119899= infin and 120596

119899= o(120579119899) Then

lim119899rarrinfin

120588119899= 0 (11)

The following is our main result

Theorem 8 Let 119870 be a nonempty closed convex subset of areal Banach space 119864 let 119878 119870 rarr 119870 be nonexpansive and let119879 119870 rarr 119870 be Lipschitz strongly pseudocontractive mappingssuch that 119901 isin 119865(119878) cap 119865(119879) = 119909 isin 119870 119878119909 = 119879119909 = 119909 and

1003817100381710038171003817119909 minus 1198781199101003817100381710038171003817 le

1003817100381710038171003817119878119909 minus 1198781199101003817100381710038171003817 forall119909 119910 isin 119870

1003817100381710038171003817119909 minus 1198791199101003817100381710038171003817 le

1003817100381710038171003817119879119909 minus 1198791199101003817100381710038171003817 forall119909 119910 isin 119870

(C)

Let 120573119899 be a sequence in [0 1] satisfying

(iv) sum119899ge1

120573119899= infin

(v) lim119899rarrinfin

120573119899= 0

For arbitrary 1199091

isin 119870 let 119909119899 be a sequence iteratively

defined by119909119899+1

= 119878119910119899

119910119899= (1 minus 120573

119899) 119909119899+ 120573119899119879119909119899 119899 ge 1

(12)

Then the sequence 119909119899 converges strongly at the common fixed

point 119901 of 119878 and 119879

Proof For strongly pseudocontractive mappings the exis-tence of a fixed point follows from Delmling [13] It is shownin [11] that the set of fixed points for strongly pseudocontrac-tions is a singleton

By (v) since lim119899rarrinfin

120573119899= 0 there exists 119899

0isin N such that

for all 119899 ge 1198990

120573119899le min 1

4119896

1 minus 119896

(1 + 119871) (1 + 3119871) (13)

where 119896 lt 12 Consider1003817100381710038171003817119909119899+1 minus 119901

1003817100381710038171003817

2= ⟨119909119899+1

minus 119901 119895 (119909119899+1

minus 119901)⟩

= ⟨119878119910119899minus 119901 119895 (119909

119899+1minus 119901)⟩

= ⟨119879119909119899+1

minus 119901 119895 (119909119899+1

minus 119901)⟩

+ ⟨119878119910119899minus 119879119909119899+1

119895 (119909119899+1

minus 119901)⟩

le 1198961003817100381710038171003817119909119899+1 minus 119901

1003817100381710038171003817

2+1003817100381710038171003817119878119910119899 minus 119879119909

119899+1

1003817100381710038171003817

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817

(14)which implies that

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817 le

1

1 minus 119896

1003817100381710038171003817119878119910119899 minus 119879119909119899+1

1003817100381710038171003817 (15)

where1003817100381710038171003817119878119910119899 minus 119879119909

119899+1

1003817100381710038171003817 le1003817100381710038171003817119878119910119899 minus 119879119910

119899

1003817100381710038171003817 +1003817100381710038171003817119879119910119899 minus 119879119909

119899+1

1003817100381710038171003817

le1003817100381710038171003817119909119899 minus 119878119910

119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119879119910

119899

1003817100381710038171003817 +1003817100381710038171003817119879119910119899 minus 119879119909

119899+1

1003817100381710038171003817

le1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817 +1003817100381710038171003817119879119909119899 minus 119879119910

119899

1003817100381710038171003817 +1003817100381710038171003817119879119910119899 minus 119879119909

119899+1

1003817100381710038171003817

le1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817 + 119871 (1003817100381710038171003817119909119899 minus 119910

119899

1003817100381710038171003817 +1003817100381710038171003817119910119899 minus 119909

119899+1

1003817100381710038171003817)

(16)1003817100381710038171003817119910119899 minus 119909

119899+1

1003817100381710038171003817 le1003817100381710038171003817119910119899 minus 119909

119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119909

119899+1

1003817100381710038171003817

=1003817100381710038171003817119910119899 minus 119909

119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119878119910

119899

1003817100381710038171003817

le1003817100381710038171003817119910119899 minus 119909

119899

1003817100381710038171003817 +1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817

(17)

Journal of Applied Mathematics 3

and consequently from (16) we obtain1003817100381710038171003817119878119910119899 minus 119879119909

119899+1

1003817100381710038171003817 le (1 + 119871)1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817 + 21198711003817100381710038171003817119909119899 minus 119910

119899

1003817100381710038171003817

le (1 + 3119871)1003817100381710038171003817119909119899 minus 119910

119899

1003817100381710038171003817

= (1 + 3119871) 1205731198991003817100381710038171003817119909119899 minus 119879119909

119899

1003817100381710038171003817

le (1 + 119871) (1 + 3119871) 1205731198991003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

(18)

Substituting (18) in (15) and using (13) we get

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817 le

(1 + 119871) (1 + 3119871)

1 minus 119896120573119899

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817

le1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

(19)

So from the above discussion we can conclude that thesequence 119909

119899minus 119901 is bounded Since 119879 is Lipschitzian so

119879119909119899minus 119901 is also bounded Let 119872

1= sup

119899ge1119909119899minus 119901 +

sup119899ge1

119879119909119899minus 119901 Also by (ii) we have

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817 = 120573119899

1003817100381710038171003817119909119899 minus 119879119909119899

1003817100381710038171003817

le 1198721120573119899

997888rarr 0

(20)

as 119899 rarr infin implying that 119909119899minus 119910119899 is bounded so let 119872

2=

sup119899ge1

119909119899minus 119910119899 + 119872

1 Further

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817 le

1003817100381710038171003817119910119899 minus 119909119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

le 1198722

(21)

which implies that 119910119899minus 119901 is bounded Therefore 119879119910

119899minus 119901

is also boundedSet

1198723= sup119899ge1

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817 + sup119899ge1

1003817100381710038171003817119879119910119899 minus 1199011003817100381710038171003817 (22)

Denote119872 = 1198721+1198722+1198723 Obviously119872 lt infin

Now from (12) for all 119899 ge 1 we obtain1003817100381710038171003817119909119899+1 minus 119901

1003817100381710038171003817

2=1003817100381710038171003817119878119910119899 minus 119901

1003817100381710038171003817

2le1003817100381710038171003817119910119899 minus 119901

1003817100381710038171003817

2 (23)

and by Lemma 6 we get1003817100381710038171003817119910119899 minus 119901

1003817100381710038171003817

2=1003817100381710038171003817(1 minus 120573

119899) 119909119899+ 120573119899119879119909119899minus 119901

1003817100381710038171003817

2

=1003817100381710038171003817(1 minus 120573

119899) (119909119899minus 119901) + 120573

119899(119879119909119899minus 119901)

1003817100381710038171003817

2

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2120573119899⟨119879119909119899minus 119901 119895 (119910

119899minus 119901)⟩

= (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2120573119899⟨119879119910119899minus 119901 119895 (119910

119899minus 119901)⟩

+ 2120573119899⟨119879119909119899minus 119879119910119899 119895 (119910119899minus 119901)⟩

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2119896120573

119899

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2

+ 2120573119899

1003817100381710038171003817119879119909119899 minus 119879119910119899

1003817100381710038171003817

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2119896120573

119899

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2

+ 2119872119871120573119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(24)

which implies that

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2le

(1 minus 120573119899)2

1 minus 2119896120573119899

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817

2+

2119872119871120573119899

1 minus 2119896120573119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

le (1 minus 120573119899)1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(25)

because by (13) we have ((1minus120573119899)(1minus2119896120573

119899)) le 1 and (1(1minus

2119896120573119899)) le 2 Hence (23) gives us

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817

2le (1 minus 120573

119899)1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817 (26)

For all 119899 ge 1 put

120588119899=1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

120579119899= 120573119899

120596119899= 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(27)

then according to Lemma 7 we obtain from (26) that

lim119899rarrinfin

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817 = 0 (28)

This completes the proof

Corollary 9 Let 119870 be a nonempty closed convex subset of areal Hilbert space119867 let 119878 119870 rarr 119870 be nonexpansive and let119879 119870 rarr 119870 be Lipschitz strongly pseudocontractive mappingssuch that 119901 isin 119865(119878) cap 119865(119879) and the condition (C) Let 120573119899 be asequence in [0 1] satisfying the conditions (iv) and (v)

For arbitrary 1199091

isin 119870 let 119909119899 be a sequence iteratively

defined by (12) Then the sequence 119909119899 converges strongly at

the common fixed point 119901 of 119878 and 119879

Example 10 As a particular case wemay choose for instance120573119899= 1119899

Remark 11 (1) The condition (C) is not new and it is due toLiu et al [14]

(2) We prove our results for a hybrid iteration schemewhich is simple in comparison to the previously knowniteration schemes

Acknowledgment

This study was supported by research funds from Dong-AUniversity

References

[1] S Ishikawa ldquoFixed points by a new iteration methodrdquo Proceed-ings of the American Mathematical Society vol 44 pp 147ndash1501974

[2] W R Mann ldquoMean value methods in iterationrdquo Proceedings ofthe American Mathematical Society vol 4 pp 506ndash510 1953

[3] D R Sahu ldquoApplications of the S-iteration process to con-strained minimization problems and split feasibility problemsrdquoFixed Point Theory vol 12 no 1 pp 187ndash204 2011

4 Journal of Applied Mathematics

[4] D R Sahu and A Petrusel ldquoStrong convergence of iterativemethods by strictly pseudocontractive mappings in BanachspacesrdquoNonlinearAnalysisTheoryMethodsampApplications vol74 no 17 pp 6012ndash6023 2011

[5] C E Chidume ldquoApproximation of fixed points of stronglypseudocontractive mappingsrdquo Proceedings of the AmericanMathematical Society vol 120 no 2 pp 545ndash551 1994

[6] C E Chidume ldquoIterative approximation of fixed points ofLipschitz pseudocontractivemapsrdquo Proceedings of the AmericanMathematical Society vol 129 no 8 pp 2245ndash2251 2001

[7] C E Chidume and C Moore ldquoFixed point iteration for pseu-docontractive mapsrdquo Proceedings of the AmericanMathematicalSociety vol 127 no 4 pp 1163ndash1170 1999

[8] C E Chidume and H Zegeye ldquoApproximate fixed pointsequences and convergence theorems for Lipschitz pseudo-contractive mapsrdquo Proceedings of the American MathematicalSociety vol 132 no 3 pp 831ndash840 2004

[9] J Schu ldquoApproximating fixed points of Lipschitzian pseudocon-tractive mappingsrdquoHouston Journal of Mathematics vol 19 no1 pp 107ndash115 1993

[10] X Weng ldquoFixed point iteration for local strictly pseudo-contractive mappingrdquo Proceedings of the American Mathemat-ical Society vol 113 no 3 pp 727ndash731 1991

[11] H Zhou and Y Jia ldquoApproximation of fixed points of stronglypseudocontractive maps without Lipschitz assumptionrdquo Pro-ceedings of the American Mathematical Society vol 125 no 6pp 1705ndash1709 1997

[12] S S Chang ldquoSome problems and results in the study ofnonlinear analysisrdquo Nonlinear Analysis vol 30 no 7 pp 4197ndash4208 1997

[13] K Delmling ldquoZeros of accretive operatorsrdquoManuscripta Math-ematica vol 13 pp 283ndash288 1974

[14] Z Liu C Feng J S Ume and S M Kang ldquoWeak and strongconvergence for common fixed points of a pair of nonexpansiveand asymptotically nonexpansivemappingsrdquoTaiwanese Journalof Mathematics vol 11 no 1 pp 27ndash42 2007

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical Problems in Engineering

Hindawi Publishing Corporationhttpwwwhindawicom

Differential EquationsInternational Journal of

Volume 2014

Applied MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical PhysicsAdvances in

Complex AnalysisJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OptimizationJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Operations ResearchAdvances in

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Function Spaces

Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of Mathematics and Mathematical Sciences

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Algebra

Discrete Dynamics in Nature and Society

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Decision SciencesAdvances in

Discrete MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Stochastic AnalysisInternational Journal of

Page 2: Research Article Strong Convergence for Hybrid S-Iteration ...downloads.hindawi.com/journals/jam/2013/705814.pdf · : is a continuous strongly pseudocontractive mapping, then the

2 Journal of Applied Mathematics

been known only in Hilbert spaces and only for Lipschitzmappings have been extended to more general Banach spaces(see eg [5ndash10] and the references cited therein)

In 1974 Ishikawa [1] proved the following result

Theorem 5 Let 119870 be a compact convex subset of a Hilbertspace 119867 and let 119879 119870 rarr 119870 be a Lipschitzian pseudocon-tractive mapping For arbitrary 119909

1isin 119870 let 119909

119899 be a sequence

defined iteratively by

119909119899+1

= (1 minus 120572119899) 119909119899+ 120572119899119879119910119899

119910119899= (1 minus 120573

119899) 119909119899+ 120573119899119879119909119899 119899 ge 1

(8)

where 120572119899 and 120573

119899 are sequences satisfying

(i) 0 le 120572119899le 120573119899le 1

(ii) lim119899rarrinfin

120573119899= 0

(iii) sum119899ge1

120572119899120573119899= infin

Then the sequence 119909119899 converges strongly at a fixed point of 119879

In [6] Chidume extended the results of Schu [9] fromHilbert spaces to the much more general class of real Banachspaces and approximated the fixed points of (strongly) pseu-docontractive mappings

In [11] Zhou and Jia gave the more general answer of thequestion raised by Chidume [5] and proved the following

If 119883 is a real Banach space with a uniformly convex dual119883lowast119870 is a nonempty bounded closed convex subset of119883 and

119879 119870 rarr 119870 is a continuous strongly pseudocontractivemapping then the Ishikawa iteration scheme convergesstrongly at the unique fixed point of 119879

In this paper we establish the strong convergence forthe hybrid 119878-iterative scheme associated with nonexpansiveand Lipschitz strongly pseudocontractive mappings in realBanach spaces We also improve the result of Zhou and Jia[11]

2 Main Results

We will need the following lemmas

Lemma 6 (see [12]) Let 119869 119864 rarr 2119864 be the normalized

duality mapping Then for any 119909 119910 isin 119864 one has

1003817100381710038171003817119909 + 1199101003817100381710038171003817

2le 119909

2+ 2 ⟨119910 119895 (119909 + 119910)⟩

forall119895 (119909 + 119910) isin 119869 (119909 + 119910)

(9)

Lemma 7 (see [10]) Let 120588119899 be nonnegative sequence satisfy-

ing

120588119899+1

le (1 minus 120579119899) 120588119899+ 120596119899 (10)

where 120579119899isin [0 1]sum

119899ge1120579119899= infin and 120596

119899= o(120579119899) Then

lim119899rarrinfin

120588119899= 0 (11)

The following is our main result

Theorem 8 Let 119870 be a nonempty closed convex subset of areal Banach space 119864 let 119878 119870 rarr 119870 be nonexpansive and let119879 119870 rarr 119870 be Lipschitz strongly pseudocontractive mappingssuch that 119901 isin 119865(119878) cap 119865(119879) = 119909 isin 119870 119878119909 = 119879119909 = 119909 and

1003817100381710038171003817119909 minus 1198781199101003817100381710038171003817 le

1003817100381710038171003817119878119909 minus 1198781199101003817100381710038171003817 forall119909 119910 isin 119870

1003817100381710038171003817119909 minus 1198791199101003817100381710038171003817 le

1003817100381710038171003817119879119909 minus 1198791199101003817100381710038171003817 forall119909 119910 isin 119870

(C)

Let 120573119899 be a sequence in [0 1] satisfying

(iv) sum119899ge1

120573119899= infin

(v) lim119899rarrinfin

120573119899= 0

For arbitrary 1199091

isin 119870 let 119909119899 be a sequence iteratively

defined by119909119899+1

= 119878119910119899

119910119899= (1 minus 120573

119899) 119909119899+ 120573119899119879119909119899 119899 ge 1

(12)

Then the sequence 119909119899 converges strongly at the common fixed

point 119901 of 119878 and 119879

Proof For strongly pseudocontractive mappings the exis-tence of a fixed point follows from Delmling [13] It is shownin [11] that the set of fixed points for strongly pseudocontrac-tions is a singleton

By (v) since lim119899rarrinfin

120573119899= 0 there exists 119899

0isin N such that

for all 119899 ge 1198990

120573119899le min 1

4119896

1 minus 119896

(1 + 119871) (1 + 3119871) (13)

where 119896 lt 12 Consider1003817100381710038171003817119909119899+1 minus 119901

1003817100381710038171003817

2= ⟨119909119899+1

minus 119901 119895 (119909119899+1

minus 119901)⟩

= ⟨119878119910119899minus 119901 119895 (119909

119899+1minus 119901)⟩

= ⟨119879119909119899+1

minus 119901 119895 (119909119899+1

minus 119901)⟩

+ ⟨119878119910119899minus 119879119909119899+1

119895 (119909119899+1

minus 119901)⟩

le 1198961003817100381710038171003817119909119899+1 minus 119901

1003817100381710038171003817

2+1003817100381710038171003817119878119910119899 minus 119879119909

119899+1

1003817100381710038171003817

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817

(14)which implies that

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817 le

1

1 minus 119896

1003817100381710038171003817119878119910119899 minus 119879119909119899+1

1003817100381710038171003817 (15)

where1003817100381710038171003817119878119910119899 minus 119879119909

119899+1

1003817100381710038171003817 le1003817100381710038171003817119878119910119899 minus 119879119910

119899

1003817100381710038171003817 +1003817100381710038171003817119879119910119899 minus 119879119909

119899+1

1003817100381710038171003817

le1003817100381710038171003817119909119899 minus 119878119910

119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119879119910

119899

1003817100381710038171003817 +1003817100381710038171003817119879119910119899 minus 119879119909

119899+1

1003817100381710038171003817

le1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817 +1003817100381710038171003817119879119909119899 minus 119879119910

119899

1003817100381710038171003817 +1003817100381710038171003817119879119910119899 minus 119879119909

119899+1

1003817100381710038171003817

le1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817 + 119871 (1003817100381710038171003817119909119899 minus 119910

119899

1003817100381710038171003817 +1003817100381710038171003817119910119899 minus 119909

119899+1

1003817100381710038171003817)

(16)1003817100381710038171003817119910119899 minus 119909

119899+1

1003817100381710038171003817 le1003817100381710038171003817119910119899 minus 119909

119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119909

119899+1

1003817100381710038171003817

=1003817100381710038171003817119910119899 minus 119909

119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119878119910

119899

1003817100381710038171003817

le1003817100381710038171003817119910119899 minus 119909

119899

1003817100381710038171003817 +1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817

(17)

Journal of Applied Mathematics 3

and consequently from (16) we obtain1003817100381710038171003817119878119910119899 minus 119879119909

119899+1

1003817100381710038171003817 le (1 + 119871)1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817 + 21198711003817100381710038171003817119909119899 minus 119910

119899

1003817100381710038171003817

le (1 + 3119871)1003817100381710038171003817119909119899 minus 119910

119899

1003817100381710038171003817

= (1 + 3119871) 1205731198991003817100381710038171003817119909119899 minus 119879119909

119899

1003817100381710038171003817

le (1 + 119871) (1 + 3119871) 1205731198991003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

(18)

Substituting (18) in (15) and using (13) we get

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817 le

(1 + 119871) (1 + 3119871)

1 minus 119896120573119899

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817

le1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

(19)

So from the above discussion we can conclude that thesequence 119909

119899minus 119901 is bounded Since 119879 is Lipschitzian so

119879119909119899minus 119901 is also bounded Let 119872

1= sup

119899ge1119909119899minus 119901 +

sup119899ge1

119879119909119899minus 119901 Also by (ii) we have

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817 = 120573119899

1003817100381710038171003817119909119899 minus 119879119909119899

1003817100381710038171003817

le 1198721120573119899

997888rarr 0

(20)

as 119899 rarr infin implying that 119909119899minus 119910119899 is bounded so let 119872

2=

sup119899ge1

119909119899minus 119910119899 + 119872

1 Further

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817 le

1003817100381710038171003817119910119899 minus 119909119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

le 1198722

(21)

which implies that 119910119899minus 119901 is bounded Therefore 119879119910

119899minus 119901

is also boundedSet

1198723= sup119899ge1

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817 + sup119899ge1

1003817100381710038171003817119879119910119899 minus 1199011003817100381710038171003817 (22)

Denote119872 = 1198721+1198722+1198723 Obviously119872 lt infin

Now from (12) for all 119899 ge 1 we obtain1003817100381710038171003817119909119899+1 minus 119901

1003817100381710038171003817

2=1003817100381710038171003817119878119910119899 minus 119901

1003817100381710038171003817

2le1003817100381710038171003817119910119899 minus 119901

1003817100381710038171003817

2 (23)

and by Lemma 6 we get1003817100381710038171003817119910119899 minus 119901

1003817100381710038171003817

2=1003817100381710038171003817(1 minus 120573

119899) 119909119899+ 120573119899119879119909119899minus 119901

1003817100381710038171003817

2

=1003817100381710038171003817(1 minus 120573

119899) (119909119899minus 119901) + 120573

119899(119879119909119899minus 119901)

1003817100381710038171003817

2

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2120573119899⟨119879119909119899minus 119901 119895 (119910

119899minus 119901)⟩

= (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2120573119899⟨119879119910119899minus 119901 119895 (119910

119899minus 119901)⟩

+ 2120573119899⟨119879119909119899minus 119879119910119899 119895 (119910119899minus 119901)⟩

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2119896120573

119899

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2

+ 2120573119899

1003817100381710038171003817119879119909119899 minus 119879119910119899

1003817100381710038171003817

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2119896120573

119899

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2

+ 2119872119871120573119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(24)

which implies that

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2le

(1 minus 120573119899)2

1 minus 2119896120573119899

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817

2+

2119872119871120573119899

1 minus 2119896120573119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

le (1 minus 120573119899)1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(25)

because by (13) we have ((1minus120573119899)(1minus2119896120573

119899)) le 1 and (1(1minus

2119896120573119899)) le 2 Hence (23) gives us

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817

2le (1 minus 120573

119899)1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817 (26)

For all 119899 ge 1 put

120588119899=1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

120579119899= 120573119899

120596119899= 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(27)

then according to Lemma 7 we obtain from (26) that

lim119899rarrinfin

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817 = 0 (28)

This completes the proof

Corollary 9 Let 119870 be a nonempty closed convex subset of areal Hilbert space119867 let 119878 119870 rarr 119870 be nonexpansive and let119879 119870 rarr 119870 be Lipschitz strongly pseudocontractive mappingssuch that 119901 isin 119865(119878) cap 119865(119879) and the condition (C) Let 120573119899 be asequence in [0 1] satisfying the conditions (iv) and (v)

For arbitrary 1199091

isin 119870 let 119909119899 be a sequence iteratively

defined by (12) Then the sequence 119909119899 converges strongly at

the common fixed point 119901 of 119878 and 119879

Example 10 As a particular case wemay choose for instance120573119899= 1119899

Remark 11 (1) The condition (C) is not new and it is due toLiu et al [14]

(2) We prove our results for a hybrid iteration schemewhich is simple in comparison to the previously knowniteration schemes

Acknowledgment

This study was supported by research funds from Dong-AUniversity

References

[1] S Ishikawa ldquoFixed points by a new iteration methodrdquo Proceed-ings of the American Mathematical Society vol 44 pp 147ndash1501974

[2] W R Mann ldquoMean value methods in iterationrdquo Proceedings ofthe American Mathematical Society vol 4 pp 506ndash510 1953

[3] D R Sahu ldquoApplications of the S-iteration process to con-strained minimization problems and split feasibility problemsrdquoFixed Point Theory vol 12 no 1 pp 187ndash204 2011

4 Journal of Applied Mathematics

[4] D R Sahu and A Petrusel ldquoStrong convergence of iterativemethods by strictly pseudocontractive mappings in BanachspacesrdquoNonlinearAnalysisTheoryMethodsampApplications vol74 no 17 pp 6012ndash6023 2011

[5] C E Chidume ldquoApproximation of fixed points of stronglypseudocontractive mappingsrdquo Proceedings of the AmericanMathematical Society vol 120 no 2 pp 545ndash551 1994

[6] C E Chidume ldquoIterative approximation of fixed points ofLipschitz pseudocontractivemapsrdquo Proceedings of the AmericanMathematical Society vol 129 no 8 pp 2245ndash2251 2001

[7] C E Chidume and C Moore ldquoFixed point iteration for pseu-docontractive mapsrdquo Proceedings of the AmericanMathematicalSociety vol 127 no 4 pp 1163ndash1170 1999

[8] C E Chidume and H Zegeye ldquoApproximate fixed pointsequences and convergence theorems for Lipschitz pseudo-contractive mapsrdquo Proceedings of the American MathematicalSociety vol 132 no 3 pp 831ndash840 2004

[9] J Schu ldquoApproximating fixed points of Lipschitzian pseudocon-tractive mappingsrdquoHouston Journal of Mathematics vol 19 no1 pp 107ndash115 1993

[10] X Weng ldquoFixed point iteration for local strictly pseudo-contractive mappingrdquo Proceedings of the American Mathemat-ical Society vol 113 no 3 pp 727ndash731 1991

[11] H Zhou and Y Jia ldquoApproximation of fixed points of stronglypseudocontractive maps without Lipschitz assumptionrdquo Pro-ceedings of the American Mathematical Society vol 125 no 6pp 1705ndash1709 1997

[12] S S Chang ldquoSome problems and results in the study ofnonlinear analysisrdquo Nonlinear Analysis vol 30 no 7 pp 4197ndash4208 1997

[13] K Delmling ldquoZeros of accretive operatorsrdquoManuscripta Math-ematica vol 13 pp 283ndash288 1974

[14] Z Liu C Feng J S Ume and S M Kang ldquoWeak and strongconvergence for common fixed points of a pair of nonexpansiveand asymptotically nonexpansivemappingsrdquoTaiwanese Journalof Mathematics vol 11 no 1 pp 27ndash42 2007

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical Problems in Engineering

Hindawi Publishing Corporationhttpwwwhindawicom

Differential EquationsInternational Journal of

Volume 2014

Applied MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical PhysicsAdvances in

Complex AnalysisJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OptimizationJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Operations ResearchAdvances in

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Function Spaces

Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of Mathematics and Mathematical Sciences

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Algebra

Discrete Dynamics in Nature and Society

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Decision SciencesAdvances in

Discrete MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Stochastic AnalysisInternational Journal of

Page 3: Research Article Strong Convergence for Hybrid S-Iteration ...downloads.hindawi.com/journals/jam/2013/705814.pdf · : is a continuous strongly pseudocontractive mapping, then the

Journal of Applied Mathematics 3

and consequently from (16) we obtain1003817100381710038171003817119878119910119899 minus 119879119909

119899+1

1003817100381710038171003817 le (1 + 119871)1003817100381710038171003817119878119909119899 minus 119878119910

119899

1003817100381710038171003817 + 21198711003817100381710038171003817119909119899 minus 119910

119899

1003817100381710038171003817

le (1 + 3119871)1003817100381710038171003817119909119899 minus 119910

119899

1003817100381710038171003817

= (1 + 3119871) 1205731198991003817100381710038171003817119909119899 minus 119879119909

119899

1003817100381710038171003817

le (1 + 119871) (1 + 3119871) 1205731198991003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

(18)

Substituting (18) in (15) and using (13) we get

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817 le

(1 + 119871) (1 + 3119871)

1 minus 119896120573119899

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817

le1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

(19)

So from the above discussion we can conclude that thesequence 119909

119899minus 119901 is bounded Since 119879 is Lipschitzian so

119879119909119899minus 119901 is also bounded Let 119872

1= sup

119899ge1119909119899minus 119901 +

sup119899ge1

119879119909119899minus 119901 Also by (ii) we have

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817 = 120573119899

1003817100381710038171003817119909119899 minus 119879119909119899

1003817100381710038171003817

le 1198721120573119899

997888rarr 0

(20)

as 119899 rarr infin implying that 119909119899minus 119910119899 is bounded so let 119872

2=

sup119899ge1

119909119899minus 119910119899 + 119872

1 Further

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817 le

1003817100381710038171003817119910119899 minus 119909119899

1003817100381710038171003817 +1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

le 1198722

(21)

which implies that 119910119899minus 119901 is bounded Therefore 119879119910

119899minus 119901

is also boundedSet

1198723= sup119899ge1

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817 + sup119899ge1

1003817100381710038171003817119879119910119899 minus 1199011003817100381710038171003817 (22)

Denote119872 = 1198721+1198722+1198723 Obviously119872 lt infin

Now from (12) for all 119899 ge 1 we obtain1003817100381710038171003817119909119899+1 minus 119901

1003817100381710038171003817

2=1003817100381710038171003817119878119910119899 minus 119901

1003817100381710038171003817

2le1003817100381710038171003817119910119899 minus 119901

1003817100381710038171003817

2 (23)

and by Lemma 6 we get1003817100381710038171003817119910119899 minus 119901

1003817100381710038171003817

2=1003817100381710038171003817(1 minus 120573

119899) 119909119899+ 120573119899119879119909119899minus 119901

1003817100381710038171003817

2

=1003817100381710038171003817(1 minus 120573

119899) (119909119899minus 119901) + 120573

119899(119879119909119899minus 119901)

1003817100381710038171003817

2

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2120573119899⟨119879119909119899minus 119901 119895 (119910

119899minus 119901)⟩

= (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2120573119899⟨119879119910119899minus 119901 119895 (119910

119899minus 119901)⟩

+ 2120573119899⟨119879119909119899minus 119879119910119899 119895 (119910119899minus 119901)⟩

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2119896120573

119899

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2

+ 2120573119899

1003817100381710038171003817119879119909119899 minus 119879119910119899

1003817100381710038171003817

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

le (1 minus 120573119899)21003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 2119896120573

119899

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2

+ 2119872119871120573119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(24)

which implies that

1003817100381710038171003817119910119899 minus 1199011003817100381710038171003817

2le

(1 minus 120573119899)2

1 minus 2119896120573119899

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817

2+

2119872119871120573119899

1 minus 2119896120573119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

le (1 minus 120573119899)1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(25)

because by (13) we have ((1minus120573119899)(1minus2119896120573

119899)) le 1 and (1(1minus

2119896120573119899)) le 2 Hence (23) gives us

1003817100381710038171003817119909119899+1 minus 1199011003817100381710038171003817

2le (1 minus 120573

119899)1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

2+ 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817 (26)

For all 119899 ge 1 put

120588119899=1003817100381710038171003817119909119899 minus 119901

1003817100381710038171003817

120579119899= 120573119899

120596119899= 4119872119871120573

119899

1003817100381710038171003817119909119899 minus 119910119899

1003817100381710038171003817

(27)

then according to Lemma 7 we obtain from (26) that

lim119899rarrinfin

1003817100381710038171003817119909119899 minus 1199011003817100381710038171003817 = 0 (28)

This completes the proof

Corollary 9 Let 119870 be a nonempty closed convex subset of areal Hilbert space119867 let 119878 119870 rarr 119870 be nonexpansive and let119879 119870 rarr 119870 be Lipschitz strongly pseudocontractive mappingssuch that 119901 isin 119865(119878) cap 119865(119879) and the condition (C) Let 120573119899 be asequence in [0 1] satisfying the conditions (iv) and (v)

For arbitrary 1199091

isin 119870 let 119909119899 be a sequence iteratively

defined by (12) Then the sequence 119909119899 converges strongly at

the common fixed point 119901 of 119878 and 119879

Example 10 As a particular case wemay choose for instance120573119899= 1119899

Remark 11 (1) The condition (C) is not new and it is due toLiu et al [14]

(2) We prove our results for a hybrid iteration schemewhich is simple in comparison to the previously knowniteration schemes

Acknowledgment

This study was supported by research funds from Dong-AUniversity

References

[1] S Ishikawa ldquoFixed points by a new iteration methodrdquo Proceed-ings of the American Mathematical Society vol 44 pp 147ndash1501974

[2] W R Mann ldquoMean value methods in iterationrdquo Proceedings ofthe American Mathematical Society vol 4 pp 506ndash510 1953

[3] D R Sahu ldquoApplications of the S-iteration process to con-strained minimization problems and split feasibility problemsrdquoFixed Point Theory vol 12 no 1 pp 187ndash204 2011

4 Journal of Applied Mathematics

[4] D R Sahu and A Petrusel ldquoStrong convergence of iterativemethods by strictly pseudocontractive mappings in BanachspacesrdquoNonlinearAnalysisTheoryMethodsampApplications vol74 no 17 pp 6012ndash6023 2011

[5] C E Chidume ldquoApproximation of fixed points of stronglypseudocontractive mappingsrdquo Proceedings of the AmericanMathematical Society vol 120 no 2 pp 545ndash551 1994

[6] C E Chidume ldquoIterative approximation of fixed points ofLipschitz pseudocontractivemapsrdquo Proceedings of the AmericanMathematical Society vol 129 no 8 pp 2245ndash2251 2001

[7] C E Chidume and C Moore ldquoFixed point iteration for pseu-docontractive mapsrdquo Proceedings of the AmericanMathematicalSociety vol 127 no 4 pp 1163ndash1170 1999

[8] C E Chidume and H Zegeye ldquoApproximate fixed pointsequences and convergence theorems for Lipschitz pseudo-contractive mapsrdquo Proceedings of the American MathematicalSociety vol 132 no 3 pp 831ndash840 2004

[9] J Schu ldquoApproximating fixed points of Lipschitzian pseudocon-tractive mappingsrdquoHouston Journal of Mathematics vol 19 no1 pp 107ndash115 1993

[10] X Weng ldquoFixed point iteration for local strictly pseudo-contractive mappingrdquo Proceedings of the American Mathemat-ical Society vol 113 no 3 pp 727ndash731 1991

[11] H Zhou and Y Jia ldquoApproximation of fixed points of stronglypseudocontractive maps without Lipschitz assumptionrdquo Pro-ceedings of the American Mathematical Society vol 125 no 6pp 1705ndash1709 1997

[12] S S Chang ldquoSome problems and results in the study ofnonlinear analysisrdquo Nonlinear Analysis vol 30 no 7 pp 4197ndash4208 1997

[13] K Delmling ldquoZeros of accretive operatorsrdquoManuscripta Math-ematica vol 13 pp 283ndash288 1974

[14] Z Liu C Feng J S Ume and S M Kang ldquoWeak and strongconvergence for common fixed points of a pair of nonexpansiveand asymptotically nonexpansivemappingsrdquoTaiwanese Journalof Mathematics vol 11 no 1 pp 27ndash42 2007

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical Problems in Engineering

Hindawi Publishing Corporationhttpwwwhindawicom

Differential EquationsInternational Journal of

Volume 2014

Applied MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical PhysicsAdvances in

Complex AnalysisJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OptimizationJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Operations ResearchAdvances in

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Function Spaces

Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of Mathematics and Mathematical Sciences

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Algebra

Discrete Dynamics in Nature and Society

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Decision SciencesAdvances in

Discrete MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Stochastic AnalysisInternational Journal of

Page 4: Research Article Strong Convergence for Hybrid S-Iteration ...downloads.hindawi.com/journals/jam/2013/705814.pdf · : is a continuous strongly pseudocontractive mapping, then the

4 Journal of Applied Mathematics

[4] D R Sahu and A Petrusel ldquoStrong convergence of iterativemethods by strictly pseudocontractive mappings in BanachspacesrdquoNonlinearAnalysisTheoryMethodsampApplications vol74 no 17 pp 6012ndash6023 2011

[5] C E Chidume ldquoApproximation of fixed points of stronglypseudocontractive mappingsrdquo Proceedings of the AmericanMathematical Society vol 120 no 2 pp 545ndash551 1994

[6] C E Chidume ldquoIterative approximation of fixed points ofLipschitz pseudocontractivemapsrdquo Proceedings of the AmericanMathematical Society vol 129 no 8 pp 2245ndash2251 2001

[7] C E Chidume and C Moore ldquoFixed point iteration for pseu-docontractive mapsrdquo Proceedings of the AmericanMathematicalSociety vol 127 no 4 pp 1163ndash1170 1999

[8] C E Chidume and H Zegeye ldquoApproximate fixed pointsequences and convergence theorems for Lipschitz pseudo-contractive mapsrdquo Proceedings of the American MathematicalSociety vol 132 no 3 pp 831ndash840 2004

[9] J Schu ldquoApproximating fixed points of Lipschitzian pseudocon-tractive mappingsrdquoHouston Journal of Mathematics vol 19 no1 pp 107ndash115 1993

[10] X Weng ldquoFixed point iteration for local strictly pseudo-contractive mappingrdquo Proceedings of the American Mathemat-ical Society vol 113 no 3 pp 727ndash731 1991

[11] H Zhou and Y Jia ldquoApproximation of fixed points of stronglypseudocontractive maps without Lipschitz assumptionrdquo Pro-ceedings of the American Mathematical Society vol 125 no 6pp 1705ndash1709 1997

[12] S S Chang ldquoSome problems and results in the study ofnonlinear analysisrdquo Nonlinear Analysis vol 30 no 7 pp 4197ndash4208 1997

[13] K Delmling ldquoZeros of accretive operatorsrdquoManuscripta Math-ematica vol 13 pp 283ndash288 1974

[14] Z Liu C Feng J S Ume and S M Kang ldquoWeak and strongconvergence for common fixed points of a pair of nonexpansiveand asymptotically nonexpansivemappingsrdquoTaiwanese Journalof Mathematics vol 11 no 1 pp 27ndash42 2007

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical Problems in Engineering

Hindawi Publishing Corporationhttpwwwhindawicom

Differential EquationsInternational Journal of

Volume 2014

Applied MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical PhysicsAdvances in

Complex AnalysisJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OptimizationJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Operations ResearchAdvances in

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Function Spaces

Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of Mathematics and Mathematical Sciences

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Algebra

Discrete Dynamics in Nature and Society

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Decision SciencesAdvances in

Discrete MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Stochastic AnalysisInternational Journal of

Page 5: Research Article Strong Convergence for Hybrid S-Iteration ...downloads.hindawi.com/journals/jam/2013/705814.pdf · : is a continuous strongly pseudocontractive mapping, then the

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical Problems in Engineering

Hindawi Publishing Corporationhttpwwwhindawicom

Differential EquationsInternational Journal of

Volume 2014

Applied MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Mathematical PhysicsAdvances in

Complex AnalysisJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OptimizationJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Operations ResearchAdvances in

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Function Spaces

Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of Mathematics and Mathematical Sciences

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Algebra

Discrete Dynamics in Nature and Society

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Decision SciencesAdvances in

Discrete MathematicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Stochastic AnalysisInternational Journal of