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A New Class of Banach Spaces with Uniform Normal Structure 被引量:6
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作者 高继 《Northeastern Mathematical Journal》 CSCD 2001年第1期103-110,共8页
Let X be a Banach space, S(X) be the unit sphere of X, φ be a function: S(X)→ S(X *) such that φ(x)∈ x, and v φ(ε) =inf 1-12x+y: x,y∈S(X), and 〈φ(x), x-y 〉≥ε, 0≤ε≤2, whe... Let X be a Banach space, S(X) be the unit sphere of X, φ be a function: S(X)→ S(X *) such that φ(x)∈ x, and v φ(ε) =inf 1-12x+y: x,y∈S(X), and 〈φ(x), x-y 〉≥ε, 0≤ε≤2, where x is the set of norm 1 supporting functionals of S(X) at x. A geometric concept, modulus of V convexity V(ε)= sup {V φ(ε), for all φ: S(X)→S(X *)}, is introduced; the properties of V(ε) and the relationship between V(ε) and other geometric concepts are discussed. The main result is that V12>0 implies normal structure. 展开更多
关键词 normal structure modulus of convexity modulus of V convexity uniformly nonsquare uniformly convex uniformly smooth V space
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NORMAL STRUCTURE AND SOME GEOMETRIC PARAMETERS RELATED TO THE MODULUS OF U-CONVEXITY IN BANACH SPACES 被引量:2
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作者 Ji Gao Satit Saejung 《Acta Mathematica Scientia》 SCIE CSCD 2011年第3期1035-1040,共6页
We present a short and simple proof of the recent result of Yang and Wang [12]. Stimulated by their idea, two geometric parameters Uax(ε) and βx (ε), both related to Gao's modulus of U-convexity of a Banach sp... We present a short and simple proof of the recent result of Yang and Wang [12]. Stimulated by their idea, two geometric parameters Uax(ε) and βx (ε), both related to Gao's modulus of U-convexity of a Banach space X, are introduced. Their properties and the relationships with normal structure are studied. Some existing results involving normal structure and fixed points for non-expansive mappings in Banach spaces are improved. 展开更多
关键词 uniform normal structure modulus of convexity ULTRAPOWER
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UNIFORM NORMAL STRUCTURE AND SOLUTIONS OF REICH’S OPEN QUESTION
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作者 曾六川 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2005年第9期1204-1211,共8页
The open question raised by Reich is studied in a Banach space with uniform normal structure, whose norm is uniformly Gateaux differentiable. Under more suitable assumptions imposed on an asymptotically nonexpansive m... The open question raised by Reich is studied in a Banach space with uniform normal structure, whose norm is uniformly Gateaux differentiable. Under more suitable assumptions imposed on an asymptotically nonexpansive mapping, an affirmative answer to Reich' s open question is given. The results presented extend and improve Zhang Shisheng' s recent ones in the following aspects : (i) Zhang' s stronger condition that the sequence of iterative parameters converges to zero is removed; (ii) Zhang' s stronger assumption that the asymptotically nonexpansive mapping has a fixed point is removed; (iii) Zhang' s stronger condition that the sequence generated by the Banach Contraction Principle is strongly convergent is also removed. Moreover, these also extend and improve the corresponding ones obtained previously by several authors including Reich, Shioji, Takahashi,Ueda and Wittmann. 展开更多
关键词 asymptotically nonexpansive mapping fixed point uniform normal structure uniformly CJateaux differentiable norm iterative approximation
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ON A CLASS OF KTHE SEQUENCE SPACES WITH NORMAL STRUCTURE
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作者 B. Zlatanov 《Acta Mathematica Scientia》 SCIE CSCD 2011年第2期576-590,共15页
In this note, we investigate the generalized modulus of convexity δ(λ) and the generalized modulus smoothness p(λ). We obtain some estimates of these moduli for X=lp. We obtain inequalities between WCS coeffici... In this note, we investigate the generalized modulus of convexity δ(λ) and the generalized modulus smoothness p(λ). We obtain some estimates of these moduli for X=lp. We obtain inequalities between WCS coefficient of a KSthe sequence space X and δX(λ). We show that, for a wide class of class the sequence spaces X, if for some ε∈(0, 9/10] holds δx(e) 〉 1/3(1- √3/2)ε, then X has normal structure. 展开更多
关键词 Weakly convergent sequence coefficient modulus of convexity generalizedmodulus of convexity normal structure
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L^0-CONVEX COMPACTNESS AND RANDOM NORMAL STRUCTURE IN L^0(F,B)
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作者 Tiexin GUO Erxin ZHANG +1 位作者 Yachao WANG George YUAN 《Acta Mathematica Scientia》 SCIE CSCD 2020年第2期457-469,共13页
Let(B,||·||)be a Banach space,(?,F,P)a probability space,and L^0(F,B)the set of equivalence classes of strong random elements(or strongly measurable functions)from(?,F,P)to(B,||·||).It is well known that L^0... Let(B,||·||)be a Banach space,(?,F,P)a probability space,and L^0(F,B)the set of equivalence classes of strong random elements(or strongly measurable functions)from(?,F,P)to(B,||·||).It is well known that L^0(F,B)becomes a complete random normed module,which has played an important role in the process of applications of random normed modules to the theory of Lebesgue-Bochner function spaces and random operator theory.Let V be a closed convex subset of B and L^0(F,V)the set of equivalence classes of strong random elements from(?,F,P)to V.The central purpose of this article is to prove the following two results:(1)L^0(F,V)is L^0-convexly compact if and only if V is weakly compact;(2)L^0(F,V)has random normal structure if V is weakly compact and has normal structure.As an application,a general random fixed point theorem for a strong random nonexpansive operator is given,which generalizes and improves several well known results.We hope that our new method,namely skillfully combining measurable selection theorems,the theory of random normed modules,and Banach space techniques,can be applied in the other related aspects. 展开更多
关键词 Complete random normed modules fixed point theorem L^0-convex compactness random normal structure random nonexpansive operators
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ON A GENERALIZED GEOMETRIC CONSTANT AND SUFFICIENT CONDITIONS FOR NORMAL STRUCTURE IN BANACH SPACES
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作者 Mina DINARVAND 《Acta Mathematica Scientia》 SCIE CSCD 2017年第5期1209-1220,共12页
In this paper, we introduce a new geometric constant C;(a, X) of a Banach space X, which is closely related to the generalized von Neumann-Jordan constant and analyze some properties of the constant. Subsequently, w... In this paper, we introduce a new geometric constant C;(a, X) of a Banach space X, which is closely related to the generalized von Neumann-Jordan constant and analyze some properties of the constant. Subsequently, we present several sufficient conditions for normal structure of a Banach space in terms of this new constant, the generalized James constant, the generalized Garc′?a-Falset coefficient and the coefficient of weak orthogonality of Sims. Our main results of the paper generalize some known results in the recent literature. 展开更多
关键词 uniform normal structure generalized Garc′?a-Falset coefficient coefficient of weak orthogonality constant CN Jp(a X) generalized James constant
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ON A GENERALIZED MODULUS OF CONVEXITY AND UNIFORM NORMAL STRUCTURE
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作者 杨长森 王丰辉 《Acta Mathematica Scientia》 SCIE CSCD 2007年第4期838-844,共7页
In this article, the authors study a generalized modulus of convexity, δ(α) (ε). Certain related geometrical properties of this modulus are analyzed. Their main result is that Banach space X has uniform normal ... In this article, the authors study a generalized modulus of convexity, δ(α) (ε). Certain related geometrical properties of this modulus are analyzed. Their main result is that Banach space X has uniform normal structure if there exists ε, 0 ≤e≤ 1, such that δ^(α)(1+ε ) 〉 (1- α)ε. 展开更多
关键词 Generalized modulus of convexity uniform normal structure ULTRAPRODUCT
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Weak Uniform Normal Structure and Fixed Points of Asymptotically Regular Semigroups
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作者 Lu Chuan ZENG 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2004年第6期977-982,共6页
Let X be a Banach space with a weak uniform normal structure and C a non–empty convex weakly compact subset of X. Under some suitable restriction, we prove that every asymptotically regular semigroup T = {T(t) : t ∈... Let X be a Banach space with a weak uniform normal structure and C a non–empty convex weakly compact subset of X. Under some suitable restriction, we prove that every asymptotically regular semigroup T = {T(t) : t ∈? S} of selfmappings on C satisfying 展开更多
关键词 Weak uniform normal structure Fixed point Exact Lipschitz constant Weakly convergent sequence coefficient Asymptotically regular semigroup
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A FIXED POINT THEOREM FOR MULTIVALUED NONEXPANSIVE MAPPINGS IN BANACH SPACES OF NORMAL STRUCTURE
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作者 解基培 《Chinese Science Bulletin》 SCIE EI 1990年第4期265-267,共3页
Since the appearance of T. C. Lim’s fixed point theorem for multivalued nonexpansive mappings in uniformly convex spaces in 1974, various generalizations and modifications have been obtained (e.g. [2, 3] and other re... Since the appearance of T. C. Lim’s fixed point theorem for multivalued nonexpansive mappings in uniformly convex spaces in 1974, various generalizations and modifications have been obtained (e.g. [2, 3] and other references in [4, 5]). However, the corresponding fixed point problem for Banach spaces of normal structure remains open. The present report shall give a positive answer to it. 展开更多
关键词 multivalued nonexpansive mapping normal structure f-quasi-invariant
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Coexistence of ferromagnetism and superconductivity in normal mental/superconductor/ferromagnet structures
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作者 郁华玲 彭菊 金本喜 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第8期554-558,共5页
We extend the Blonder, Tinkham and Klapwijk theory to the study of the inverse proximity effects in the normal mental/superconductor/ferromagnet structures. In the superconducting film, there are the gapless supercond... We extend the Blonder, Tinkham and Klapwijk theory to the study of the inverse proximity effects in the normal mental/superconductor/ferromagnet structures. In the superconducting film, there are the gapless superconductivity and the spin-dependent density of states both within and without the energy gap. It indicates an appearance of the inverse-proximity-effect-induced ferromagnetism and a coexistence of ferromagnetism and superconductivity near the interface. The influence of exchange energy in the ferromagnet and barrier strength at the superconductor/ferromagnet interface on the inverse proximity effects is discussed. 展开更多
关键词 coexistence of ferromagnetism and superconductivity inverse proximity effects normal mental/superconductor/ferromagnet structures
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Synthesis and Structure of Ag_3PSe_4
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作者 马宏伟 郭国聪 +4 位作者 陈文通 邓镭 周国伟 董振超 黄锦顺 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2003年第2期161-164,共4页
The title compound Ag3PSe4 was synthesized by the reaction of Ag powder, P2Se5 and Se in a molar ratio of 1:1:1 at 500 C and structurally characterized by X-ray crystallography. The crystal belongs to orthorhombic, sp... The title compound Ag3PSe4 was synthesized by the reaction of Ag powder, P2Se5 and Se in a molar ratio of 1:1:1 at 500 C and structurally characterized by X-ray crystallography. The crystal belongs to orthorhombic, space group Pmn21 with cell parameters: a = 7.689(4), b = 6.660(3), c = 6.379(4) , V = 326.7(3) 3, Z = 2, Dc = 6.816 g/cm3, Mr = 670.42, F(000) = 584, m = 31.302 mm-1, R = 0.0606, wR = 0.1289 and S = 1.012. The 3-D structure can be regarded as constructed from the stacking of puckered AgPSe honeycomb-like sheets along the c direction, in which the Ag, P and Se atoms are bonded to each other to form a chair-like six-membered ring, and the rings then build the sheets by sharing edges. 展开更多
关键词 solid state reaction normal tetrahedral structure metal chalcogenophosphide
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FIXED POINTS OF NONEXPANSIVE MAPPINGS ON STAR-SHAPED SUBSETS OF A CONVEX METRIC SPACE
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作者 邓磊 丁协平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1992年第2期135-141,共7页
In this paper, we give some characteristic properties of star-shaped sets which include a subset of a convex metric space. Using the characteristic properties, we discuss the existence problems of fixed points of none... In this paper, we give some characteristic properties of star-shaped sets which include a subset of a convex metric space. Using the characteristic properties, we discuss the existence problems of fixed points of nonexpansive type mappings on star-shaped subsets of convex metric spaces, which generalize the recent results obtained by Ding Xie-ping, Beg and Azam. Finally, we give an example which shows that our generalizations are essential. 展开更多
关键词 star-shaped set star centre normal structure of a star-shaped set
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Synthesis and Re-refinement of Cu_3PSe_4
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作者 马宏伟 郭国聪 +4 位作者 周国伟 王明盛 林善伙 董振超 黄锦顺 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2002年第3期288-291,共4页
The title compound Cu3PSe4 was synthesized by the reaction of CuCl, P2Se5 and Se in a molar ratio of 1:1:1 at 500 C and structurally characterized by X-ray crystallography. The crystal belongs to orthorhombic, space g... The title compound Cu3PSe4 was synthesized by the reaction of CuCl, P2Se5 and Se in a molar ratio of 1:1:1 at 500 C and structurally characterized by X-ray crystallography. The crystal belongs to orthorhombic, space group Pmn21 with cell parameters: a = 7.685(2), b = 6.656(1), c = 6.377(1) , V = 326.2(1) 3, Z = 2, Dc = 5.472 g/cm3, Mr = 537.43, F(000) = 476, m = 32.12 mm-1, R = 0.0642, wR = 0.1481 and S = 1.037. The 3-D structure can be regarded as constructed from the alternately stacking of [Cu(2)Se4] tetrahedral layers and Cu(1)PSe tetrahedral layers along the b direction, in which the Cu(2)Se layer is comprised of corner-sharing [Cu(2)Se4] tetrahedra along the a and c directions, and the Cu(1)PSe layer is consisted of alternately corner-sharing [Cu(1)Se4] tetrahedra and [PSe4] tetrahedra along the a and c directions. 展开更多
关键词 solid state reaction normal tetrahedral structure metal chalcogenophosphide
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Structure normal velocity reconstruction withsparse measurement points
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作者 MAO Rongfu ZHU Haichao 《Chinese Journal of Acoustics》 CSCD 2018年第1期60-68,共9页
To achieve normal velocity reconstruction of a vibrating surface with sparse mea- surement points, a reconstruction method is proposed by exploiting of acoustic radiation modes as expansion functions, which are capabl... To achieve normal velocity reconstruction of a vibrating surface with sparse mea- surement points, a reconstruction method is proposed by exploiting of acoustic radiation modes as expansion functions, which are capable of describing the geometric shape of a vibrating surface. Firstly, acoustic radiation modes of the vibrating surface are calculated and the rela- tionship between normal velocity and acoustic radiation modes is built. Then actual measured normal velocity values are expressed by corresponding acoustic radiation modes and the expan- sion coefficients are calculated. Subsequently, all normal velocity values can be reconstructed by the obtained expansion coefficients. Experimental validations have been performed by a double-layer steel cylindrical shell with enclosed ends in an anechoic water tank. Two cases with different wavenumber components distribution were designed by a vibration shaker and a rotor device respectively. Two experimental results both show that actual vibration distribution cannot be revealed exactly by the sparse measurement points, which corresponds to severe loss of vibration related wavenumber components. On the other hand, normal velocity and corresponding wavenumber components can be restored accurately in both two wavenumber components distribution cases according to the proposed method, which demonstrates obvious effectiveness of the proposed method. 展开更多
关键词 structure normal velocity reconstruction withsparse measurement points
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Fibrous Structure of Connective Tissue of Normal Human Lamina Cribrosa.
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作者 Ren Zeqin. Dept Ophthal, the First Teaching Hospital, BMU, Beijing 100034 《Chinese Medical Journal》 SCIE CAS CSCD 1995年第7期78-78,共1页
Fibrous components and structural morphology of the connective tissue of the lamina cribrosa obtained from 35 normal human autopsy eyes were examined by histochemical staining, transmission electron microscopic and co... Fibrous components and structural morphology of the connective tissue of the lamina cribrosa obtained from 35 normal human autopsy eyes were examined by histochemical staining, transmission electron microscopic and computer- 展开更多
关键词 Fibrous structure of Connective Tissue of normal Human Lamina Cribrosa
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RF-thermal-structural-RF coupled analysis on a travelling wave disk-loaded accelerating structure 被引量:2
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作者 裴士伦 池云龙 +2 位作者 张敬如 侯汨 李小平 《Chinese Physics C》 SCIE CAS CSCD 2012年第6期555-560,共6页
The travelling wave (TW) disk-loaded accelerating structure is one of the key components in normal conducting (NC) linear accelerators, and has been studied for many years. In the design process, usually after the... The travelling wave (TW) disk-loaded accelerating structure is one of the key components in normal conducting (NC) linear accelerators, and has been studied for many years. In the design process, usually after the dimensions of each cell and the two couplers are finalized, the structure is fabricated and tuned, and then the whole structure RF characteristics are measured by using a vector network analyzer. Before fabrication, the whole structure characteristics (including RF, thermal and structural ones) are less simulated due to the limited capability of currently available computers. In this paper, we described a method for performing RF-thermal-structural-RF coupled analysis on a TW disk-loaded structure using only one PC. In order to validate our method, we first analyzed and compared our RF simulation results on the 3 m long BEPC Ⅱ structure with the corresponding experimental results, which shows very good consistency. Finally, the RF-thermal-structure-RF coupled analysis results on the 1.35 m long NSC KIPT linac accelerating structure are presented. 展开更多
关键词 RF-thermal-structural-RF coupled analysis travelling wave disk-loaded accelerating structure normal conducting ANSYS
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The Effect of Particle Shape on the Structure and Rheological Properties of Carbon-based Particle Suspensions 被引量:4
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作者 Ran Niu Jiang Gong +2 位作者 许东华 Tao Tang 孙昭艳 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2015年第11期1550-1561,共12页
The structure and rheological properties of carbon-based particle suspensions, i.e., carbon black(CB), multi-wall carbon nanotube(MWNT), graphene and hollow carbon sphere(HCS) suspended in polydimethylsiloxane(... The structure and rheological properties of carbon-based particle suspensions, i.e., carbon black(CB), multi-wall carbon nanotube(MWNT), graphene and hollow carbon sphere(HCS) suspended in polydimethylsiloxane(PDMS), are investigated. In order to study the effect of particle shape on the structure and rheological properties of suspensions, the content of surface oxygen-containing functional groups of carbon-based particles is controlled to be similar. Original spherical-like CB(fractal filler), rod-like MWNT and sheet-like graphene form large agglomerates in PDMS, while spherical HCS particles disperse relatively well in PDMS. The dispersion state of carbon-based particles affects the critical concentration of forming a rheological percolation network. Under weak shear, negative normal stress differences(ΔN) are observed in CB, MWNT and graphene suspensions, while ΔN is nearly zero for HCS suspensions. It is concluded that the vorticity alignment of CB, MWNT and graphene agglomerates under shear results in the negative ΔN. However, no obvious structural change is observed in HCS suspension under weak shear, and accordingly, the ΔN is almost zero. 展开更多
关键词 Particle shape Surface chemistry Negative normal stress differences structure Interaction
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ON THE EXISTENCE OF FIXED POINTS FOR MAPPINGS OF ASYMPTOTICALLY NONEXPANSIVE TYPE 被引量:2
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作者 ZENGLuchuan 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2004年第2期188-196,共9页
Let C be a nonempty weakly compact convex subset of a Banach space X, and T : C →C a mapping of asymptotically nonexpansive type. Then there hold the following conclusions: (i) if X has uniform normal structure and l... Let C be a nonempty weakly compact convex subset of a Banach space X, and T : C →C a mapping of asymptotically nonexpansive type. Then there hold the following conclusions: (i) if X has uniform normal structure and limsup |||TjN||| < N(X)~1/(N(X)) , where|||TjN||| is the exact Lipschitz constant of TjN , N is some positive integer, and N(X) is the normal structure coefficient of X, then T has a fixed point; (ii) if X is uniformly convex in every direction and has weak uniform normal structure, then T has a fixed point. 展开更多
关键词 Mapping of asymptotically nonexpansive type fixed point uniform normal structure weak uniform normal structure uniform convexity in every direction.
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On Characterization of Iterative Approximation for Asymptotically Pseudocontractive Mappings
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作者 曾六川 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2005年第2期279-286,共8页
Let C be a nonempty bounded closed convex subset of a Banach space X, and T : C → C be uniformly L-Lipschitzian with L ≥ 1 and asymptotically pseudocontractive with a sequence {kn}(?)[1, ∞), limn→∞ kn = 1. Fix u ... Let C be a nonempty bounded closed convex subset of a Banach space X, and T : C → C be uniformly L-Lipschitzian with L ≥ 1 and asymptotically pseudocontractive with a sequence {kn}(?)[1, ∞), limn→∞ kn = 1. Fix u ∈ C. For each n ≥ 1, xn is a unique fixed point of the contraction Sn(x) = (1 - (tn)/(Lkn))u + (tn)/(Lkn)Tnx(?)x ∈ C, where {tn}(?)[0,1). Under suitable conditions, the strong convergence of the sequence{xn}to a fixed point of T is characterized. 展开更多
关键词 fixed point asymptotically pseudocontractive mapping uniform Lipschitzian mapping uniform normal structure Banach contraction principle.
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ON THE EXISTENCE OF FIXED POINTS FOR LIPSCHITZIAN SEMIGROUPS IN BANACH SPACES 被引量:1
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作者 ZENG LUCHUAN, YANG YALI Department of Matematics, Shanghai Normal University, Shanghai 200234, China. 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2001年第3期397-404,共8页
Let C be a nonempty bounded subset of a p-uniformly convex Banach space X, and T = {T(t): t S} be a Lipschitzian semigroup on C with lim inf |||T(t)||| < Np, where Np is n→ t s the normal structure coefficient of ... Let C be a nonempty bounded subset of a p-uniformly convex Banach space X, and T = {T(t): t S} be a Lipschitzian semigroup on C with lim inf |||T(t)||| < Np, where Np is n→ t s the normal structure coefficient of X. Suppose also there exists a nonempty bounded closed convex subset E of C with the following properties: (P1)x: E implies ωω(χ) C E; (P2)T is asymptotically regular on E. The authors prove that there exists a z E such that T(s)z = z for all s S. Fruther, under the similar condition, the existence of fixed points of Lipschitzian semigroups in a uniformly convex Banach space is discussed. 展开更多
关键词 Fixed points Lipschitzian semigroups Asymptotic regularity normal structure coefficient Asymptotic center
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