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2. A note on a paper of I.D. Arand̄elović on asymptotic contractions
- Author
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Jachymski, Jacek
- Subjects
- *
CONTRACTIONS (Topology) , *FIXED point theory , *METRIC spaces , *MATHEMATICAL proofs , *MATHEMATICAL analysis , *GENERALIZED spaces - Abstract
Abstract: W.A. Kirk [W.A. Kirk, Fixed points of asymptotic contractions, J. Math. Anal. Appl. 277 (2003) 645–650] defined the notion of an asymptotic contraction on a metric space and using ultrapower techniques he gave a nonconstructive proof of an asymptotic version of the Boyd–Wong fixed point theorem. Subsequently, I.D. Arand̄elović [I.D. Arand̄elović, On a fixed point theorem of Kirk, J. Math. Anal. Appl. 301 (2005) 384–385] established somewhat more general version of Kirk''s result and he gave an elementary proof of it. However, our purpose is to show that there is an error in this proof and, moreover, Arand̄elović''s theorem is false. We also explain how to correct this result. [Copyright &y& Elsevier]
- Published
- 2009
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3. Spreading dynamics of an impulsive reaction-diffusion model with shifting environments.
- Author
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Zhang, Yurong, Yi, Taishan, and Chen, Yuming
- Subjects
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DISCRETE-time systems , *DYNAMICAL systems , *DISCRETE systems , *REACTION-diffusion equations - Abstract
This paper focuses on the effects of environmental improvement and worsening on the spread and invasion of populations with birth pulse. We propose an impulsive reaction-diffusion model with a shifting environment to describe the dynamics of species with distinct reproduction stage and dispersal stage. First, the impulsive reaction-diffusion model is reduced to a discrete-time recursive system defined by a discrete map. Next, with the aid of the appropriate test function and comparison principle, we obtain some sufficient conditions on the nonexistence and uniqueness of nontrivial fixed points of the discrete map. This, combined with the abstract theory of spatially non-translation dynamical systems, enables us to establish the existence of traveling wave solutions and the asymptotic propagation properties of the model. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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4. Extension of the fixed point theory to tuned mass dampers with piezoelectric stack energy harvester.
- Author
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Anh, N.D., Tuan, Vu Anh, Thang, Pham Manh, and Linh, N.N.
- Subjects
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FIXED point theory , *TUNED mass dampers , *ENERGY harvesting , *ELECTRICAL load - Abstract
• Formulation of TMD-PSEH system attached to an undamped primary structure. • Extension of the fixed point theory to the TMD-PSEH system. • Close-form expression of optimal tuning, damping, and resistance ratios. • Insight into the power flow analysis. • Performance of the system along with attendant numerical simulations. A tuned mass damper with a piezoelectric stack energy harvester (TMD-PSEH) is a passive vibration control device for the dual purpose of absorbing vibration and harvesting energy. This paper develops the fixed point theory for the optimal design of a TMD-PSEH attached to an undamped primary structure under harmonic external excitation. It has been proven that the existence of two fixed points of the amplitude-frequency curve doest not depend on the damping of the primary structure. Based on the requirements for suppressing the vibration of the primary structure and enlarging the harvested power, the analytical expressions for the optimal tuning, damping, and resistance ratios are determined. It is found that the minimum damping ratio occurs in the vicinity of the electrical resistance ratio α = 1 for various values of the electromechanical coupling coefficient. Power flow analysis is carried out resulting in closed-form expressions of instantaneous and average powers. Numerical examinations of the system with the obtained optimal parameters are performed demonstrating a very good compatibility between theory and computation. In addition, the effect of damping in the primary structure is also investigated. It is shown that not only the vibration of the primary structure effectively reduces, but also a large amount of the harvested energy can be captured in the main resonance region. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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5. Existence and regularity of solutions for a class of fractional Laplacian problems.
- Author
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Wu, Pengcheng, Huang, Yisheng, and Zhou, Yuying
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INTERPOLATION , *LAPLACIAN operator - Abstract
In this paper, we first establish a modified Marcinkiewicz interpolation result, and using this result, we obtain a new regularity result for a fractional Laplacian problem on a bounded C 1 , 1 -domain Ω in R N , and we also obtain a new regularity result for then fractional problem on unbounded Ω = R N by using the Stampacchia truncation method. Next, by the Leray-Schauder fixed point theorem we obtain the existence of solutions for a class of fractional Laplacian problems with weak growth conditions on the nonlinearities. Finally, as an application, we prove the existence of positive solutions for a fractional Laplacian problem which has an exponential growth nonlinearity. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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6. Two porosity theorems for nonexpansive mappings in hyperbolic spaces.
- Author
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Reich, Simeon and Zaslavski, Alexander J.
- Subjects
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POROSITY , *MATHEMATICS theorems , *NONEXPANSIVE mappings , *HYPERBOLIC spaces , *BANACH spaces , *MATHEMATICAL bounds - Abstract
In a previous paper of ours we used the notion of porosity to show that most of the nonexpansive self-mappings of bounded, closed and convex subsets of a Banach space are contractive and possess a unique fixed point which is the uniform limit of all iterates. In this paper we extend this result to nonexpansive self-mappings of closed and convex sets in a Banach space which are not necessarily bounded. As a matter of fact, it turns out that our results are true for all complete hyperbolic metric spaces. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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7. The fixed point property for some generalized nonexpansive mappings and renormings.
- Author
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Betiuk-Pilarska, A. and Domínguez Benavides, T.
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FIXED point theory , *NONEXPANSIVE mappings , *BANACH spaces , *SCHAUDER bases , *ISOMORPHISM (Mathematics) - Abstract
In 2008, T. Suzuki [33] defined one of most relevant extensions of the notion of nonexpansivity. This notion was extended in [15] defining the, so called, C λ -mappings. In the last years, some papers have appeared trying to extend the most important results about existence of fixed points for nonexpansive mappings to this wider class of mappings (see, for instance, [2,5,9,10,15] ). In this paper we continue this project proving that Banach spaces with extended unconditional bases satisfy the fixed point property for C λ -mappings if the unconditional constant of the basis is small enough. We also begin a new project on renorming with the fixed point property for C λ -mappings, proving that any separable Banach space can be renormed to satisfy the fixed point property for C λ -mappings in a stable sense, that is, the space with the new norm satisfies the fixed point property which, in addition, is inherited by those isomorphic spaces which are close to it in the sense of the Banach–Mazur distance. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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8. Fixed points and entropy of endomorphisms on simple abelian varieties.
- Author
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Herrig, Thorsten
- Subjects
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ENDOMORPHISMS , *ITERATIVE methods (Mathematics) , *ABELIAN varieties , *FIXED point theory , *NUMBER theory , *EIGENVALUES - Abstract
Abstract In this paper we investigate fixed-point numbers and entropies of endomorphisms on abelian varieties. It was shown quite recently that the number of fixed-points of an iterated endomorphism on a simple complex torus is either periodic or grows exponentially. Criteria to decide whether a given endomorphism is of the one type or the other are still missing. Our first result provides such criteria for simple abelian varieties in terms of the possible types of endomorphism algebras. The number of fixed-points depends on the eigenvalues and we exactly show which analytic eigenvalues occur. This insight is also the starting point to ask for the entropy of an endomorphism. Our second result offers criteria for an endomorphism to be of zero or positive entropy. The entropy is computed as the logarithm of a real number and our third result characterizes the algebraic structure of this number. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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9. A sum operator equation and applications to nonlinear elastic beam equations and Lane–Emden–Fowler equations
- Author
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Zhai, Chengbo and Anderson, Douglas R.
- Subjects
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OPERATOR theory , *SUMMABILITY theory , *NONLINEAR theories , *ELASTICITY , *BANACH spaces , *EXISTENCE theorems , *CONCAVE functions , *FIXED point theory - Abstract
Abstract: This paper is concerned with an operator equation on ordered Banach spaces, where A is an increasing α-concave operator, B is an increasing sub-homogeneous operator and C is a homogeneous operator. The existence and uniqueness of its positive solutions is obtained by using the properties of cones and a fixed point theorem for increasing general β-concave operators. As applications, we utilize the fixed point theorems obtained in this paper to study the existence and uniqueness of positive solutions for two classes nonlinear problems which include fourth-order two-point boundary value problems for elastic beam equations and elliptic value problems for Lane–Emden–Fowler equations. [Copyright &y& Elsevier]
- Published
- 2011
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10. Approximate fixed points of α-nonexpansive mappings.
- Author
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Amini-Harandi, A., Fakhar, M., and Hajisharifi, H.R.
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FIXED point theory , *BANACH spaces , *APPROXIMATION theory , *SUBSET selection , *MATHEMATICAL bounds - Abstract
In this paper, we define the class of ( α , β ) -nonexpansive mappings which is properly larger than the class of α -nonexpansive mappings and prove that every ( α , β ) -nonexpansive mapping T : C → C has an approximate fixed point sequence, where C is a nonempty bounded subset of a Banach space X , α > 0 and β ≥ 0 . This, in particular, gives an affirmative answer to the open question posed by Ariza-Ruiz and et al. concerning the existence of an approximate fixed point sequence for α -nonexpansive mappings, Ariza-Ruiz et al. (2016) [4] . [ABSTRACT FROM AUTHOR]
- Published
- 2018
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11. Existence and exponential stability for impulsive neutral stochastic functional differential equations driven by fBm with noncompact semigroup via Mönch fixed point.
- Author
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Deng, Sufang, Shu, Xiao-Bao, and Mao, Jianzhong
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STOCHASTIC difference equations , *SEMIGROUPS (Algebra) , *HILBERT space , *HAUSDORFF spaces , *EXPONENTIAL stability , *FIXED point theory - Abstract
In this paper, we investigate the existence and exponential stability of mild solutions for a class of impulsive neutral stochastic functional differential equations driven by fBm with noncompact semigroup in Hilbert spaces. Sufficient conditions for the existence of mild solutions are obtained using the Hausdorff measure of noncompactness and the Mönch fixed point theorem. Further, we establish a new impulsive-integral inequality to prove the exponential stability of mild solutions in the mean square moment. Finally, an example is presented to illustrate our obtained results. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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- View/download PDF
12. On the general solution and hyperstability of the general radical quintic functional equation in quasi-β-Banach spaces.
- Author
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EL-Fassi, Iz-iddine
- Subjects
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STABILITY theory , *FUNCTIONAL equations , *BANACH spaces , *MATHEMATICAL mappings , *REAL numbers , *VECTOR spaces - Abstract
The goal of this paper is to study the general solution of the following general radical quintic functional equation f ( a x 5 + b y 5 5 ) = r f ( x ) + s f ( y ) for f a mapping from the field of real numbers into a vector space, where a , b , r , s are fixed nonzero reals. Also, we prove the generalized hyperstability results for the general radical quintic functional equation by using the fixed point theorem (cf. Dung and Hang (2018) [15] , Theorem 2.1) in quasi- β -Banach spaces. Namely, we show, under some weak natural assumptions, functions satisfying the above equation approximately (in some sense) must be actually solutions to it. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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13. Moduli R(a,X) and M(X) of direct sums of Banach spaces.
- Author
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Szczepanik, Mariusz
- Subjects
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BANACH spaces , *FIXED point theory , *MODULI theory , *NONEXPANSIVE mappings , *BANACH lattices - Abstract
The moduli R ( a , X ) and M ( X ) , introduced by Domínguez Benavides, play an important role in the fixed point theory for nonexpansive mappings. In the paper we show that if inf i ∈ I M ( X i ) > 1 , then M ( ( ⨁ i ∈ I X i ) Z ) > 1 , where ( ⨁ i ∈ I X i ) Z is the direct sum of Banach spaces X i with respect to a Banach lattice Z , under some conditions for Z and I . Similar results are obtained for the modulus R ( a , X ) . [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. Mixed equilibrium problems and optimization problems
- Author
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Yao, Yonghong, Aslam Noor, M., Zainab, S., and Liou, Yeong-Cheng
- Subjects
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MATHEMATICAL optimization , *FIXED point theory , *NONEXPANSIVE mappings , *STOCHASTIC convergence , *ITERATIVE methods (Mathematics) , *MATHEMATICAL analysis - Abstract
Abstract: In this paper, we introduce and analyze a new hybrid iterative algorithm for finding a common element of the set of solutions of mixed equilibrium problems and the set of fixed points of an infinite family of nonexpansive mappings. Furthermore, we prove some strong convergence theorems for the hybrid iterative algorithm under some mild conditions. We also discuss some special cases. Results obtained in this paper improve the previously known results in this area. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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15. Fixed point theorems for multi-valued contractions in complete metric spaces
- Author
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Ćirić, Ljubomir
- Subjects
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SET theory , *MATHEMATICS , *AGGREGATED data , *ARITHMETIC - Abstract
Abstract: In this paper the concept of a contraction for multi-valued mappings in a metric space is introduced and the existence theorems for fixed points of such contractions in a complete metric space are proved. Presented results generalize and improve the recent results of Y. Feng, S. Liu [Y. Feng, S. Liu, Fixed point theorems for multi-valued contractive mappings and multi-valued Caristi type mappings, J. Math. Anal. Appl. 317 (2006) 103–112], D. Klim, D. Wardowski [D. Klim, D. Wardowski, Fixed point theorems for set-valued contractions in complete metric spaces, J. Math. Anal. Appl. 334 (2007) 132–139] and several others. The method used in the proofs of our results is new and is simpler than methods used in the corresponding papers. Two examples are given to show that our results are genuine generalization of the results of Feng and Liu and Klim and Wardowski. [Copyright &y& Elsevier]
- Published
- 2008
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16. Semigroups generated by pseudo-contractive mappings under the Nagumo condition
- Author
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Hester, Anthony and Morales, Claudio H.
- Subjects
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BANACH spaces , *COMPLEX variables , *DIFFERENTIAL equations , *CALCULUS - Abstract
Abstract: Let X be a Banach space whose dual space is uniformly convex. We demonstrate that, for any demicontinuous, weakly Nagumo, k-pseudo-contractive mapping with closed domain, weakly generates a semigroup on . In this paper, we project the consequences of this result on fixed point theory. In particular, we show that if (id est, if T is strongly pseudo-contractive), then T has a unique fixed point. This implies that, if T is pseudo-contractive () and is closed, bounded, and convex, then T has at least one fixed point. Consequently, any demicontinuous pseudo-contractive mapping (for an appropriate C) has a fixed point, which has been an important open question in fixed point theory for quite some time. In a subsequent paper, we explore the consequences of the semigroup result on the existence of solutions to certain partial differential equations. The semigroup result directly implies the existence of unique global solutions to time evolution equations of the form where A is a combination of derivatives. The fixed point results from this paper imply the existence of solutions to partial differential equations of the form . [Copyright &y& Elsevier]
- Published
- 2008
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17. On a general class of multi-valued weakly Picard mappings
- Author
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Berinde, Mădălina and Berinde, Vasile
- Subjects
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SET theory , *MATHEMATICS , *AGGREGATED data , *FIXED point theory - Abstract
Abstract: The concept of weak contraction from the case of single-valued mappings is extended to multi-valued mappings and then corresponding convergence theorems for the Picard iteration associated to a multi-valued weak contraction are obtained. The main results in this paper extend, improve and unify a multitude of classical results in the fixed point theory of single and multi-valued contractive mappings and also improve recent results from the paper [P.Z. Daffer, H. Kaneko, Fixed points of generalized contractive multi-valued mappings, J. Math. Anal. Appl. 192 (1995), 655–666]. [Copyright &y& Elsevier]
- Published
- 2007
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18. The necessary and sufficient condition for the convergence of Ishikawa iteration on an arbitrary interval
- Author
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Qing, Yuan and Qihou, Liu
- Subjects
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FIXED point theory , *CONTINUOUS functions , *STOCHASTIC convergence , *MATHEMATICAL functions - Abstract
Abstract: As an important iteration, the Mann and Ishikawa iteration has extensive application in fixed point theory. In 1991, David Borwein and Jonathan Borwein proved the convergence of the Mann iteration on a closed bounded interval in their paper. In this paper, we will extend their result to an arbitrary interval and to the Ishikawa iteration, indicating the necessary and sufficient condition for the convergence of Ishikawa iteration of continuous functions on an arbitrary interval. [Copyright &y& Elsevier]
- Published
- 2006
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19. Some new stability results of a Cauchy-Jensen equation in incomplete normed spaces.
- Author
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Ramezani, Maryam and Baghani, Hamid
- Abstract
In this paper, by using a new fixed point alternative, we establish a new generalization of the Hyers-Ulam-Rassias stability concerning a Cauchy-Jensen functional equation in normed spaces which are not necessarily Banach spaces. Moreover, our paper consists of several non-trivial examples which signify the motivation of such investigations. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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20. The generalized hyperstability of general linear equations in quasi-Banach spaces.
- Author
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Dung, Nguyen Van and Hang, Vo Thi Le
- Subjects
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LINEAR equations , *BANACH spaces , *METRIC spaces , *MATHEMATICAL proofs , *FIXED point theory - Abstract
In this paper, we study the hyperstability for the general linear equation in the setting of quasi-Banach spaces. We first extend the fixed point result of Brzdek et al. [5, Theorem 1] in metric spaces to b -metric spaces, in particular to quasi-Banach spaces. Then we use this result to generalize the main results on the hyperstability for the general linear equation in Banach spaces to quasi-Banach spaces. We also show that we can not omit the assumption of completeness in [5, Theorem 1] . As a consequence, we conclude that we need more explanations to replace a normed space by its completion in the proofs of some results in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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21. Shape preserving properties of univariate Lototsky–Bernstein operators.
- Author
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Xu, Xiao-Wei, Zeng, Xiao-Ming, and Goldman, Ron
- Subjects
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UNIVARIATE analysis , *CONVEX functions , *LINEAR operators , *OPERATOR theory , *STOCHASTIC convergence - Abstract
The main goal of this paper is to study shape preserving properties of univariate Lototsky–Bernstein operators L n ( f ) based on Lototsky–Bernstein basis functions. The Lototsky–Bernstein basis functions b n , k ( x ) ( 0 ≤ k ≤ n ) of order n are constructed by replacing x in the i th factor of the generating function for the classical Bernstein basis functions of degree n by a continuous nondecreasing function p i ( x ) , where p i ( 0 ) = 0 and p i ( 1 ) = 1 for 1 ≤ i ≤ n . These operators L n ( f ) are positive linear operators that preserve constant functions, and a non-constant function γ n p ( x ) . If all the p i ( x ) are strictly increasing and strictly convex, then γ n p ( x ) is strictly increasing and strictly convex as well. Iterates L n M ( f ) of L n ( f ) are also considered. It is shown that L n M ( f ) converges to f ( 0 ) + ( f ( 1 ) − f ( 0 ) ) γ n p ( x ) as M → ∞ . Like classical Bernstein operators, these Lototsky–Bernstein operators enjoy many traditional shape preserving properties. For every ( 1 , γ n p ( x ) ) -convex function f ∈ C [ 0 , 1 ] , we have L n ( f ; x ) ≥ f ( x ) ; and by invoking the total positivity of the system { b n , k ( x ) } 0 ≤ k ≤ n , we show that if f is ( 1 , γ n p ( x ) ) -convex, then L n ( f ; x ) is also ( 1 , γ n p ( x ) ) -convex. Finally we show that if all the p i ( x ) are monomial functions, then for every ( 1 , γ n + 1 p ( x ) ) -convex function f , L n ( f ; x ) ≥ L n + 1 ( f ; x ) if and only if p 1 ( x ) = ⋯ = p n ( x ) = x . [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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22. φ − (h,e)-concave operators and applications.
- Author
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Zhai, Chengbo and Wang, Li
- Subjects
- *
OPERATOR theory , *SET theory , *ITERATIVE methods (Mathematics) , *FIXED point theory , *UNIQUENESS (Mathematics) , *BOUNDARY value problems - Abstract
In this article, by introducing a new set and a new concept of φ − ( h , e ) -concave operators, and by using the cone theory and monotone iterative method, we present some new existence and uniqueness theorems of fixed points for increasing φ − ( h , e ) -concave operators without requiring the existence of upper and lower solutions. As an application, we establish the existence and uniqueness of a nontrivial solution for a new form of fractional differential equation with integral boundary conditions. The main results of this paper improve and extend some known results, and present a new method to study nonlinear equation problems. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
23. Ky-Fan inequality, Nash equilibria in some idempotent and harmonic convex structure
- Author
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Ilknur Yesilce, Walter Briec, and Sabire Yazıcı Fen Edebiyat Fakültesi
- Subjects
Pure mathematics ,Computer Science::Computer Science and Game Theory ,Applied Mathematics ,Ky Fan inequality ,Stochastic game ,Inverse B-convexity (B−1-convexity) ,Structure (category theory) ,Inverse ,Harmonic Structures ,Fixed point ,Convexity ,Ky-Fan Inequality ,Nash Equilibrium ,symbols.namesake ,Nash equilibrium ,Fixed Points ,symbols ,Limit (mathematics) ,Analysis ,Mathematics - Abstract
B -convexity is defined as a suitable Peano-Kuratowski limit of linear convexities. An alternative idempotent convex structure called inverse B -convexity was recently proposed in the literature. This paper continues and extends some investigation started in these papers. In particular we focus on the Ky-Fan inequality and prove the existence of a Nash equilibrium for inverse B -convex games. This we do by considering a suitable “harmonic” topological structure which allows to establish a KKM theorem as well as some important related properties. Among other things a coincidence theorem is established. The paper also establishes fixed point results and Nash equilibriums properties in the case where two different convex topological structures are merged. It follows that one can consider a large class of games where the players may optimize their payoff subject to different forms of convexity. Among other things an inverse B -convex version of the Debreu-Gale-Nikaido theorem is proposed.
- Published
- 2022
24. A note on the admissibility of modular function spaces.
- Author
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Caponetti, Diana and Lewicki, Grzegorz
- Subjects
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MODULAR functions , *FUNCTION spaces , *MATHEMATICAL mappings , *ADMISSIBLE sets , *FIXED point theory - Abstract
In this paper we prove the admissibility of modular function spaces E ρ considered and defined by Kozłowski in [17] . As an application we get that any compact and continuous mapping T : E ρ → E ρ has a fixed point. Moreover, we prove that the same holds true for any retract of E ρ . [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
25. Statistics of partial permutations via Catalan matrices.
- Author
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Cheng, Yen-Jen, Eu, Sen-Peng, and Hsu, Hsiang-Chun
- Subjects
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COLUMNS , *CATALAN numbers , *PERMUTATIONS , *SEEDS - Abstract
A generalized Catalan matrix (a n , k) n , k ≥ 0 is generated by two seed sequences s = (s 0 , s 1 , ...) and t = (t 1 , t 2 , ...) together with a recurrence relation. By taking s ℓ = 2 ℓ + 1 and t ℓ = ℓ 2 we can interpret a n , k as the number of partial permutations, which are n × n 0 , 1 -matrices of k zero rows with at most one 1 in each row or column. In this paper we prove that most of fundamental statistics and some set-valued statistics on permutations can also be defined on partial permutations and be encoded in the seed sequences. Results on two interesting permutation families, namely the connected permutations and cycle-up-down permutations, are also given. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
26. Compactness and the fixed point property in ℓ1.
- Author
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Domínguez-Benavides, T. and Japón, M.
- Subjects
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COMPACT spaces (Topology) , *FIXED point theory , *MATHEMATICAL mappings , *BANACH spaces , *MATHEMATICAL analysis - Abstract
In this paper we prove that compactness can be characterized by means of the existence of a fixed point for some classes of mappings defined on convex closed subsets of the space ℓ 1 . Nominally, our result involves nonexpansive mappings, uniformly Lipschitzian mappings and cascading nonexpansive mappings. We also extend the results to some more general classes of Banach spaces. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
27. The multiplicity of positive solutions for a class of nonlocal elliptic problem.
- Author
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Yan, Baoqiang and Wang, Dechen
- Subjects
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ELLIPTIC equations , *MULTIPLICITY (Mathematics) , *FIXED point theory , *PARTIAL differential equations , *MATHEMATICAL analysis - Abstract
In this paper, using the theory of fixed point index, we prove some results on the multiplicity of positive solutions for a class of nonlocal elliptic problem. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
28. Fixed points of endomorphisms on two-dimensional complex tori.
- Author
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Bauer, Thomas and Herrig, Thorsten
- Subjects
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FIXED point theory , *ENDOMORPHISMS , *ASYMPTOTIC expansions , *ALGEBRAIC geometry , *EIGENVALUES - Abstract
In this paper we investigate fixed-point numbers of endomorphisms on complex tori. Specifically, motivated by the asymptotic perspective that has turned out in recent years to be so fruitful in Algebraic Geometry, we study how the number of fixed points behaves when the endomorphism is iterated. Our first result shows that the fixed-points function of an endomorphism on a two-dimensional complex torus can have only three different kinds of behaviours, and we characterize these behaviours in terms of the analytic eigenvalues. Our second result focuses on simple abelian surfaces and provides criteria for the fixed-points behaviour in terms of the possible types of endomorphism algebras. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
29. The demiclosedness principle for mean nonexpansive mappings.
- Author
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Gallagher, Torrey M.
- Subjects
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NONEXPANSIVE mappings , *CONVEX sets , *BANACH spaces , *MATHEMATICAL domains , *MATHEMATICAL bounds , *FIXED point theory - Abstract
In this paper, we establish the demiclosedness principle for the class of mean nonexpansive mappings, introduced in 2007 by Goebel and Japón Pineda, defined on closed, convex subsets of Banach spaces satisfying Opial's condition. We also establish the demiclosedness principle for a subclass of the mean nonexpansive maps whose domains are closed, bounded, convex sets in uniformly convex spaces. These results extend known demiclosedness results for nonexpansive maps and lead to some fixed point results for mean nonexpansive maps which partially answer an open question posed by Goebel and Japón Pineda. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
30. A coincidence point theorem for sequentially continuous mappings.
- Author
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Bonanno, Gabriele, Candito, Pasquale, and Motreanu, Dumitru
- Subjects
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COINCIDENCE theory , *MATHEMATICAL mappings , *CRITICAL point theory , *EXISTENCE theorems , *NONLINEAR differential equations , *DERIVATIVES (Mathematics) , *BOUNDARY value problems - Abstract
The aim of this paper is to present a coincidence point theorem for sequentially weakly continuous maps. Moreover, as a consequence, a critical point theorem for functionals possibly containing a nonsmooth part is obtained. Finally, as an application, existence results for nonlinear differential problems depending also on the derivative of the solution are established. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
31. Fixed point properties for semigroups of nonlinear mappings on unbounded sets.
- Author
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Lau, Anthony To-Ming and Zhang, Yong
- Subjects
- *
FIXED point theory , *SEMIGROUPS (Algebra) , *NONLINEAR theories , *MATHEMATICAL mappings , *MATHEMATICAL bounds , *SET theory - Abstract
A well-known result of W. Ray asserts that if C is an unbounded convex subset of a Hilbert space, then there is a nonexpansive mapping T : C → C that has no fixed point. In this paper we establish some common fixed point properties for a semitopological semigroup S of nonexpansive mappings acting on a closed convex subset C of a Hilbert space, assuming that there is a point c ∈ C with a bounded orbit and assuming that certain subspace of C b ( S ) has a left invariant mean. Left invariant mean (or amenability) is an important notion in harmonic analysis of semigroups and groups introduced by von Neumann in 1929 [28] and formalized by Day in 1957 [5] . In our investigation we use the notion of common attractive points introduced recently by S. Atsushiba and W. Takahashi. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
32. On convergence of iteration processes for nonexpansive semigroups in uniformly convex and uniformly smooth Banach spaces.
- Author
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Kozlowski, Wojciech M.
- Subjects
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STOCHASTIC convergence , *ITERATIVE methods (Mathematics) , *GROUP theory , *BANACH spaces , *TOPOLOGY - Abstract
Let C be a closed, bounded and convex subset of a uniformly convex and uniformly smooth Banach space. Let { T t } t ≥ 0 be a strongly-continuous nonexpansive semigroup on C . Consider the iterative process defined by the sequence of equations x k + 1 = c k T t k + 1 ( x k + 1 ) + ( 1 − c k ) x k . We prove that, under certain conditions, the sequence { x k } converges weakly to a common fixed point of the semigroup { T t } t ≥ 0 . There are known results on convergence of such iterative processes for nonexpansive semigroups in Hilbert spaces and Banach spaces with the Opial property. However, many important spaces like L p for 1 ≤ p ≠ 2 do not possess the Opial property. In this paper, we do not assume the Opial property. We do assume instead that X is uniformly convex and uniformly smooth. L p for p > 1 are prime examples of such spaces. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
33. Uniform nonsquareness and locally uniform nonsquareness in Orlicz–Bochner function spaces and applications.
- Author
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Shang, Shaoqiang and Cui, Yunan
- Subjects
- *
UNIFORM algebras , *ORLICZ spaces , *BOCHNER integrals , *FUNCTION spaces , *FIXED point theory - Abstract
In this paper, criteria for uniform nonsquareness and locally uniform nonsquareness of Orlicz–Bochner function spaces equipped with the Orlicz norm are given. Although, criteria for uniform nonsquareness and locally uniform nonsquareness in Orlicz function spaces were known, we can easily deduce them from our main results. Moreover, we give a sufficient condition for an Orlicz–Bochner function space to have the fixed point property. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
34. Fixed points of Mizoguchi–Takahashi contraction on a metric space with a graph and applications.
- Author
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Sultana, Asrifa and Vetrivel, V.
- Subjects
- *
FIXED point theory , *CONTRACTION operators , *METRIC spaces , *GRAPH theory , *MATHEMATICAL mappings , *NONLINEAR systems - Abstract
Abstract: In this paper we extend Mizoguchi–Takahashi's fixed point theorem for multi-valued mappings on a metric space endowed with a graph. As an application, we establish a fixed point theorem on an ε-chainable metric space for mappings satisfying Mizoguchi–Takahashi contractive condition uniformly locally. Also, we establish a result on the convergence of successive approximations for certain operators (not necessarily linear) on a Banach space as another application. Consequently, this result yields the Kelisky–Rivlin theorem on iterates of the Bernstein operators on the space and also enables us study the asymptotic behaviour of iterates of some nonlinear Bernstein type operators on . [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
35. Fixed point theorems and the Ulam–Hyers stability in non-Archimedean cone metric spaces.
- Author
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Huy, Nguyen Bich and Thanh, Tran Dinh
- Subjects
- *
FIXED point theory , *STABILITY theory , *METRIC spaces , *EXISTENCE theorems , *MATHEMATICAL proofs , *OPERATOR theory - Abstract
Abstract: Let be a metric space with a K-valued non-Archimedean metric p. In this paper, we prove the existence and approximation of a fixed point for operators satisfying the contractive condition in the form , where is an increasing operator. Then, we study the generalized Ulam–Hyers stability of fixed point equations. We next obtain an extension of the Krasnoselskii fixed point theorem for the sum of two operators. Finally, an application to functional equations is given. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
36. Several extensions of the Abian–Brown Fixed Point Theorem and their applications to extended and generalized Nash equilibria on chain-complete posets.
- Author
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Li, Jinlu
- Subjects
- *
FIXED point theory , *GENERALIZATION , *NASH equilibrium , *MATHEMATICAL mappings , *SET-valued maps , *MATHEMATICAL proofs - Abstract
Abstract: In this paper, we provide several extensions of the Abian–Brown Fixed Point Theorem from single-valued mappings to set-valued mappings on chain-complete posets. Then we examine some non-monetized, non-cooperative games where both the collections of the strategies and the ranges of the utilities for the players are posets. By applying the extensions of the Abian–Brown Fixed Point Theorem and by applying the order-preserving property of mappings, we prove some existence theorems of extended and generalized Nash equilibria for non-monetized, non-cooperative games on chain-complete posets. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
37. Ergodic theorems for hybrid sequences in a Hilbert space with applications.
- Author
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Djafari Rouhani, Behzad
- Subjects
- *
MATHEMATICS theorems , *HILBERT space , *GENERALIZATION , *MATHEMATICAL sequences , *FIXED point theory , *STOCHASTIC convergence - Abstract
Abstract: In this paper, we introduce the notion of generalized hybrid sequences, extending the notion of nonexpansive sequences introduced and studied in our previous work Djafari Rouhani (1981, 1990, 1990, 1997, 2002, 2004, 2002) [2–8], and prove ergodic and convergence theorems for such sequences in a Hilbert space . Subsequently, we apply our results to prove new fixed point theorems for generalized hybrid mappings, first introduced in Kocourek et al. (2010) [14], Takahashi and Takeuchi (2011) [20], defined on arbitrary nonempty subsets of . [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
38. On properties of meromorphic solutions for difference equations concerning gamma function.
- Author
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Chen, Zong-Xuan
- Subjects
- *
MEROMORPHIC functions , *DIFFERENCE equations , *GAMMA functions , *POLYNOMIALS , *EXPONENTS , *STOCHASTIC convergence , *FIXED point theory - Abstract
Abstract: In this paper, we mainly consider the properties of differences of meromorphic solutions for the difference equation concerning a Gamma function, where and are nonzero polynomials. By these properties, we deduce that a Gamma function satisfies that for every , and have same zeros, at most except exceptional zeros, where denotes the order of growth of a meromorphic function , and and denote the exponents of convergence of fixed points and zeros of respectively. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
39. Multivalued mixed variational inequalities with locally Lipschitzian and locally cocoercive multivalued mappings
- Author
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Alleche, Boualem
- Subjects
- *
MANY-valued logic , *MATHEMATICAL inequalities , *MATHEMATICAL mappings , *SURROGATE-based optimization , *CONVEXITY spaces , *BANACH spaces , *PARAMETER estimation - Abstract
Abstract: In this paper, we study the problem of solving multivalued mixed variational inequalities. By using some sequential approximation techniques of fixed point theory, we solve the multivalued mixed variational inequalities involving locally Lipschitzian or locally cocoercive multivalued mappings. We establish that the convexity of the multivalued mapping values is not needed and construct by using the Banach contraction principle converging sequences to the solutions. Also, we show how to choose regularization parameters to compute these solutions. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
40. Mann iteration process for asymptotic pointwise nonexpansive mappings in metric spaces
- Author
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Ibn Dehaish, B.A., Khamsi, M.A., and Khan, A.R.
- Subjects
- *
ITERATIVE methods (Mathematics) , *NONEXPANSIVE mappings , *METRIC spaces , *MATHEMATICAL bounds , *FIXED point theory , *STOCHASTIC convergence - Abstract
Abstract: Let be a complete 2-uniformly convex metric space. Let be a nonempty, bounded, closed, and convex subset of , and let be an asymptotic pointwise nonexpansive mapping. In this paper, we prove that the modified Mann iteration process defined by converges in a weaker sense to a fixed point of . [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
41. Attouch–Théra duality revisited: Paramonotonicity and operator splitting
- Author
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Bauschke, Heinz H., Boţ, Radu I., Hare, Warren L., and Moursi, Walaa M.
- Subjects
- *
DUALITY theory (Mathematics) , *SPLITTING extrapolation method , *MONOTONE operators , *MATHEMATICAL optimization , *STOCHASTIC convergence , *HILBERT space , *APPROXIMATION theory - Abstract
Abstract: The problem of finding the zeros of the sum of two maximally monotone operators is of fundamental importance in optimization and variational analysis. In this paper, we systematically study Attouch–Théra duality for this problem. We provide new results related to Passty’s parallel sum, to Eckstein and Svaiter’s extended solution set, and to Combettes’ fixed point description of the set of primal solutions. Furthermore, paramonotonicity is revealed to be a key property because it allows for the recovery of all primal solutions given just one arbitrary dual solution. As an application, we generalize the best approximation results by Bauschke, Combettes and Luke [H.H. Bauschke, P.L. Combettes, D.R. Luke, A strongly convergent reflection method for finding the projection onto the intersection of two closed convex sets in a Hilbert space, Journal of Approximation Theory 141 (2006) 63–69] from normal cone operators to paramonotone operators. Our results are illustrated through numerous examples. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
42. An extension of Mehta theorem with applications
- Author
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Wu, Ying-Lian, Huang, Chien-Hao, and Chu, Liang-Ju
- Subjects
- *
EXISTENCE theorems , *PROOF theory , *FIXED point theory , *MEASURE theory , *GENERALIZATION , *MATHEMATICAL mappings - Abstract
Abstract: A remarkable fundamental theorem established by Mehta plays an important role in proving existence of fixed points, maximal elements, and equilibria in abstract economies. In this paper, we extend Himmelbergʼs measure of precompactness to the general setting of -spaces and obtain a generalization of Mehtaʼs theorem. As an application, we develop some new fixed point theorems involving a kind of condensing mappings. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
43. Disjunctive networks and update schedules
- Author
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Goles, Eric and Noual, Mathilde
- Subjects
- *
SEQUENTIAL analysis , *PERIODIC functions , *DYNAMICS , *ROBUST control , *DISJUNCTION (Logic) , *MATHEMATICAL analysis - Abstract
Abstract: In this paper, we present a study of the dynamics of disjunctive networks under all block-sequential update schedules. We also present an extension of this study to more general fair periodic update schedules, that is, periodic update schedules that do not update some elements much more often than some others. Our main aim is to classify disjunctive networks according to the robustness of their dynamics with respect to changes of their update schedules. To study this robustness, we focus on one property, that of being able to cycle dynamically. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
44. Differential and integral equations with Henstock–Kurzweil integrable functions
- Author
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Heikkilä, S.
- Subjects
- *
NUMERICAL solutions to differential equations , *NUMERICAL solutions to integral equations , *HENSTOCK-Kurzweil integral , *MATHEMATICAL mappings , *FUNCTIONAL differential equations , *DISCONTINUOUS functions , *BANACH spaces , *BANACH lattices - Abstract
Abstract: In this paper we apply fixed point theorems for increasing mappings in ordered normed spaces to prove existence and comparison results for solutions of discontinuous functional differential and integral equations containing Henstock–Kurzweil integrable functions. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
45. Fixed point iteration processes for asymptotic pointwise nonexpansive mappings in Banach spaces
- Author
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Kozlowski, W.M.
- Subjects
- *
ITERATIVE methods (Mathematics) , *FIXED point theory , *ASYMPTOTES , *MATHEMATICAL mappings , *BANACH spaces , *CONVEX functions - Abstract
Abstract: Let X be a uniformly convex Banach space with the Opial property. Let be an asymptotic pointwise nonexpansive mapping, where C is bounded, closed and convex subset of X. In this paper, we prove that the generalized Mann and Ishikawa processes converge weakly to a fixed point of T. In addition, we prove that for compact asymptotic pointwise nonexpansive mappings acting in uniformly convex Banach spaces, both processes converge strongly to a fixed point. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
46. Fixed point theory for a class of generalized nonexpansive mappings
- Author
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García-Falset, Jesús, Llorens-Fuster, Enrique, and Suzuki, Tomonari
- Subjects
- *
FIXED point theory , *NONEXPANSIVE mappings , *EXISTENCE theorems , *ASYMPTOTIC expansions , *MATHEMATICAL analysis - Abstract
Abstract: In this paper we introduce two new classes of generalized nonexpansive mapping and we study both the existence of fixed points and their asymptotic behavior. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
47. Negative circuits and sustained oscillations in asynchronous automata networks
- Author
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Richard, Adrien
- Subjects
- *
LOGICAL prediction , *FEEDBACK control systems , *INTERSECTION graph theory , *DIFFERENTIABLE dynamical systems , *INTERVAL analysis , *FIXED point theory - Abstract
Abstract: The biologist René Thomas conjectured, twenty years ago, that the presence of a negative feedback circuit in the interaction graph of a dynamical system is a necessary condition for this system to produce sustained oscillations. In this paper, we state and prove this conjecture for asynchronous automata networks, a class of discrete dynamical systems extensively used to model the behaviors of gene networks. As a corollary, we obtain the following fixed point theorem: given a product X of n finite intervals of integers, and a map F from X to itself, if the interaction graph associated with F has no negative circuit, then F has at least one fixed point. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
48. Existence results for semilinear differential equations with nonlocal and impulsive conditions
- Author
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Fan, Zhenbin and Li, Gang
- Subjects
- *
SEMIGROUPS (Algebra) , *FIXED point theory , *EXISTENCE theorems , *LINEAR differential equations , *APPROXIMATION theory , *LIPSCHITZ spaces , *MATHEMATICAL analysis - Abstract
Abstract: This paper is concerned with the existence for impulsive semilinear differential equations with nonlocal conditions. Using the techniques of approximate solutions and fixed point, existence results are obtained, for mild solutions, when the impulsive functions are only continuous and the nonlocal item is Lipschitz in the space of piecewise continuous functions, is not Lipschitz and not compact, is continuous in the space of Bochner integrable functions, respectively. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
49. Multiple fixed points of a sum operator and applications
- Author
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Zhao, Zengqin
- Subjects
- *
FIXED point theory , *OPERATOR theory , *EXISTENCE theorems , *NONLINEAR operators , *CONVEX functions , *NONLINEAR integral equations - Abstract
Abstract: This paper considers existence of multiple positive fixed points for some nonlinear operators, a particular case of the operators is sum of an e-concave operator and an e-convex operator. Then we apply the results to nonlinear integral equations. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
50. Existence of solutions and multiple solutions for a class of weighted -Laplacian system
- Author
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Zhang, Qihu, Liu, Xiaopin, and Qiu, Zhimei
- Subjects
- *
EXISTENCE theorems , *NUMERICAL solutions to boundary value problems , *LAPLACIAN operator , *FIXED point theory , *CRITICAL point theory , *PARTIAL differential operators , *MATHEMATICAL analysis - Abstract
Abstract: This paper investigates the existence of solutions for a class of weighted -Laplacian ordinary system boundary value problems, the sufficient conditions for the existence of solutions have been given via Leray–Schauder''s degree, and the existence of multiple solutions has been discussed via critical point theory. As an application, we discussed the existence of the radial solutions for the -Laplacian partial differential system boundary value problems. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
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