12 results
Search Results
Now showing 1 - 10 of 12
Article Citation - WoS: 17Citation - Scopus: 27Fixed Point Theorems in New Generalized Metric Spaces(Springer Basel Ag, 2016) Karapinar, Erdal; Karapınar, Erdal; O'Regan, Donal; Roldan Lopez de Hierro, Antonio Francisco; Shahzad, Naseer; Karapınar, Erdal; Mathematics; MathematicsThe aim of our paper is to present new fixed point theorems under very general contractive conditions in generalized metric spaces which were recently introduced by Jleli and Samet in [Fixed Point Theory Appl. 2015 (2015), doi:10.1186/s13663-015-0312-7]. Although these spaces are not endowed with a triangle inequality, these spaces extend some well known abstract metric spaces (for example, b-metric spaces, Hitzler-Seda metric spaces, modular spaces with the Fatou property, etc.). We handle several types of contractive conditions. The main theorems we present involve a reflexive and transitive binary relation that is not necessarily a partial order. We give a counterexample to a recent fixed point result of Jleli and Samet. Our results extend and unify recent results in the context of partially ordered abstract metric spaces.Article Citation - WoS: 26Citation - Scopus: 26Coupled Coincidence Points for Mixed Monotone Operators in Partially Ordered Metric Spaces(Springer Heidelberg, 2012) Karapinar, Erdal; Karapınar, Erdal; Van Luong, Nguyen; Thuan, Nguyen Xuan; Karapınar, Erdal; Mathematics; MathematicsIn this paper, we give and prove some coupled coincidence point theorems for mappings F : X x X -> X and g : X -> X in partially ordered metric space X, where F has the mixed g-monotone property. Our results improve and generalize the results of Bhaskar and Lakshmikantham (Nonlinear Anal TMA 65: 1379-1393, 2006), Luong and Thuan (Bull Math Anal Appl 2(4): 16-24, 2010), Harjani et al. (Nonlinear Anal 74: 1749-1760, 2011) and Choudhury et al. (Ann Univ Ferrara 57: 1-16, 2011). We also give some examples to illustrate our results.Article Citation - WoS: 43A Common Fixed Point Theorem for Cyclic Operators on Partial Metric Spaces(Univ Nis, Fac Sci Math, 2012) Karapinar, Erdal; Karapınar, Erdal; Shobkolaei, Nabi; Sedghi, Shaban; Vaezpour, S. Mansour; Karapınar, Erdal; Mathematics; MathematicsIn this paper, we prove a common fixed point theorem for two self-mappings satisfying certain conditions over the class of partial metric spaces. In particular, the main theorem of this manuscript extends some well-known fixed point theorems in the literature on this topic.Article Citation - WoS: 11Citation - Scopus: 7Edelstein Type Fixed Point Theorems(Tusi Mathematical Research Group, 2011) Karapinar,E.; Karapınar, Erdal; Karapınar, Erdal; Mathematics; MathematicsRecently, Suzuki [Nonlinear Anal. 71 (2009), no. 11, 5313-5317.] published a paper on which Edelstein’s fixed theorem was generalized. In this manuscript, we give some theorems which are the generalization of the fixed theorem of Suzuki’s Theorems and thus Edelstein’s result [J. London Math. Soc. 37 (1962), 74-79]. © 2011, Duke University Press. All rights reserved.Article Citation - WoS: 173Fixed Point Theory for Cyclic Weak Φ-Contraction(Pergamon-elsevier Science Ltd, 2011) Karapinar, Erdal; Karapınar, Erdal; Karapınar, Erdal; Mathematics; MathematicsIn this manuscript, the notion of cyclic weak phi-contraction is considered. It is shown that a self-mapping T on a complete metric space X has a fixed point if it satisfied cyclic weak phi-contraction. (C) 2010 Elsevier Ltd. All rights reserved.Article Citation - WoS: 30Citation - Scopus: 37Θ-Metric Space: a Generalization(Hindawi Ltd, 2013) Khojasteh, Farshid; Karapınar, Erdal; Karapinar, Erdal; Radenovic, Stojan; Karapınar, Erdal; Mathematics; MathematicsWe introduce the notion of theta-metric as a generalization of a metric by replacing the triangle inequality with a more generalized inequality. We investigate the topology of the spaces induced by a theta-metric and present some essential properties of it. Further, we give characterization of well-known fixed point theorems, such as the Banach and Caristi types in the context of such spaces.Article Citation - Scopus: 1Discussion on the Equivalence of W-Distances With Ω-Distances(Yokohama Publications, 2015) Roldán-López-De-Hierro,A.-F.; Karapınar, Erdal; Karapinar,E.; Karapınar, Erdal; Mathematics; MathematicsIn this manuscript, we study some relationships between w-distances on metric spaces and Ω-distances on G*-metric spaces. Concretely we show that the class of all w-distances on metric spaces is a subclass of all Ω-distances on G*-metric spaces. Then, researchers must be careful because some recent results about w-distances (for instances, in the topic of fixed point theory) can be seen as simple consequences of their corresponding results about Ω-distances. In this sense, we show how to translate some results between different metric models. © 2015.Article Citation - WoS: 33Citation - Scopus: 34Iterative Approximation of Fixed Points for Presic Type f-contraction Operators(Univ Politehnica Bucharest, Sci Bull, 2016) Abbas, M.; Karapınar, Erdal; Berzig, M.; Nazir, T.; Karapinar, E.; Karapınar, Erdal; Mathematics; Mathematics; MathematicsWe study the convergence of the Presic type k-step iterative process for a class of operators f : X-k -> X satisfying Presic type F-contractive condition in the setting of metric spaces. As an applications of the result presented herein, we derive global attractivity results for a class of matrix difference equations. Numerical experiments are also presented to illustrate the theoretical findings.Article Citation - WoS: 146Citation - Scopus: 157On the Solutions of Fractional Differential Equations Via Geraghty Type Hybrid Contractions(Ministry Communications & High Technologies Republic Azerbaijan, 2021) Adiguzel, Rezan Sevinik; Sevinik Adıgüzel, Rezan; Aksoy, Umit; Aksoy, Ümit; Karapinar, Erdal; Karapınar, Erdal; Erhan, Inci M.; Erhan, İnci; Sevinik Adıgüzel, Rezan; Aksoy, Ümit; Karapınar, Erdal; Erhan, İnci; Mathematics; Mathematics; MathematicsThe aim of this article is twofold. Firstly, to study fixed points of mappings on b metric spaces satisfying a general contractive condition called Geraghty type hybrid contraction. Secondly, to apply the theoretical results to the problem of existence and uniqueness of solutions of boundary value problems with integral boundary conditions associated with a certain type of nonlinear fractional differential equations. The conditions for the existence of fixed points for Geraghty type hybrid contractions are determined and several consequences of the main results are deduced. Some examples on boundary value problems for nonlinear fractional differential equations of order 3 < alpha <= 4 are provided, where the existence and uniqueness of solutions are shown by using Geraghty type contractions.Article On Pairs of $ell$-Köthe Spaces(2010) Karapınar, ErdalLet $ell$ be a Banach sequence space with a monotone norm $parallel centerdot parallel_{ell}$, in which the canonical system ($e_i$) is a normalized unconditional basis. Let $a = (a_i), a_i rightarrow infty, lambda=(lambda_i)$ be sequences of positive numbers. We study the problem on isomorphic classification of pairs $F = biggl(K^{ell} biggl( exp biggl(-frac{1}{p}a_i biggr)biggr),K^{ell}biggl(exp biggl(-frac{1}{p}a_i + lambda_i biggr)biggr)biggr)$. For this purpose, we consider the sequence of so-called m-rectangle characteristics $mu^F_m$. It is shown that the system of all these characteristics is a complete quasidiagonal invariant on the class of pairs of finite-type $ell$-power series spaces. By using analytic scale and a modification of some invariants (modified compound invariants) it is proven that m-rectangular characteristics are invariant on the class of such pairs. Deriving the characteristic $tilde{beta}$ from the characteristic $beta$, and using the interpolation method of analytic scale, we are able to generalize some results of Chalov, Dragilev, and Zahariuta (Pair of finite type power series spaces, Note di Mathematica 17, 121–142, 1997).
