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Now showing 1 - 10 of 62
  • Article
    Citation - WoS: 15
    Contractive Multivalued Maps in Terms of q-functions on Complete Quasimetric Spaces
    (Springer international Publishing Ag, 2014) Karapinar, Erdal; Romaguera, Salvador; Tirado, Pedro
    In this paper we prove the existence of a fixed point for multivalued maps satisfying a contraction condition in terms of Q-functions, and via Bianchini-Grandolfi gauge functions, for complete T-0-quasipseudometric spaces. Our results extend, improve, and generalize some recent results in the literature. We present some examples to validate and illustrate our results.
  • Article
    Citation - WoS: 172
    Citation - Scopus: 190
    Interpolative Reich-Rus Type Contractions on Partial Metric Spaces
    (Mdpi, 2018) Karapinar, Erdal; Agarwal, Ravi; Aydi, Hassen
    By giving a counter-example, we point out a gap in the paper by Karapinar (Adv. Theory Nonlinear Anal. Its Appl. 2018, 2, 85-87) where the given fixed point may be not unique and we present the corrected version. We also state the celebrated fixed point theorem of Reich-Rus-Ciric in the framework of complete partial metric spaces, by taking the interpolation theory into account. Some examples are provided where the main result in papers by Reich (Can. Math. Bull. 1971, 14, 121-124; Boll. Unione Mat. Ital. 1972, 4, 26-42 and Boll. Unione Mat. Ital. 1971, 4, 1-11.) is not applicable.
  • Article
    Citation - WoS: 35
    Citation - Scopus: 46
    Some unique fixed point theorems for rational contractions in partially ordered metric spaces
    (Springeropen, 2013) Arshad, Muhammad; Karapinar, Erdal; Ahmad, Jamshaid
    In this paper, we prove some unique fixed point results for an operator T satisfying certain rational contraction condition in a partially ordered metric space. Our results generalize the main result of Jaggi (Indian J. Pure Appl. Math. 8(2):223-230, 1977). We give several examples to show that our results are proper generalization of the existing one. MSC: 47H10, 54H25, 46J10, 46J15.
  • Article
    Citation - WoS: 21
    Citation - Scopus: 23
    Best Proximity Points of Generalized Almost Ψ-Geraghty Contractive Non-Self
    (Springer international Publishing Ag, 2014) Aydi, Hassen; Karapinar, Erdal; Erhan, Inci M.; Salimi, Peyman
    In this paper, we introduce the new notion of almost psi-Geraghty contractive mappings and investigate the existence of a best proximity point for such mappings in complete metric spaces via the weak P-property. We provide an example to validate our best proximity point theorem. The obtained results extend, generalize, and complement some known fixed and best proximity point results from the literature.
  • Article
    Citation - WoS: 46
    Citation - Scopus: 49
    Fixed Point Theorems for Generalized (α* - Ψ)-Ciric Contractive Multivalued Operators in b-metric Spaces
    (int Scientific Research Publications, 2016) Bota, Monica-Felicia; Chifu, Cristian; Karapinar, Erdal
    In this paper we introduce the notion (alpha(*) - psi)- Ciric-type contractive multivalued operator and investigate the existence and uniqueness of fixed point for such a mapping in b-metric spaces. The well-posedness of the fixed point problem and the Ulam-Hyres stability is also studied. (C) 2016 All rights reserved.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 14
    Existence of a Solution of Integral Equations Via Fixed Point Theorem
    (Springeropen, 2013) Gulyaz, Selma; Karapinar, Erdal; Rakocevic, Vladimir; Salimi, Peyman
    In this paper, we establish a solution to the following integral equation: u(t) = integral(T)(0) G(t, s)f(s, u(s)) ds for all t is an element of [0,T], (1) where T > 0, f : [0, T] x R -> R and G : [0, T] x [0, T] -> [0, infinity) are continuous functions. For this purpose, we also obtain some auxiliary fixed point results which generalize, improve and unify some fixed point theorems in the literature.
  • Article
    Citation - WoS: 77
    Citation - Scopus: 81
    α-admissible mappings and related fixed point theorems
    (Springeropen, 2013) Hussain, Nawab; Karapinar, Erdal; Salimi, Peyman; Akbar, Farhana
    In this paper, we prove the existence and uniqueness of a fixed point for certain alpha-admissible contraction mappings. Our results generalize and extend some well-known results on the topic in the literature. We consider some examples to illustrate the usability of our results.
  • Article
    Citation - WoS: 63
    Citation - Scopus: 75
    Α-Ψ Contraction Type Mappings and Some Related Fixed Point Results
    (Univ Nis, Fac Sci Math, 2014) Karapinar, Erdal
    In this paper, we consider a generalization of alpha-psi-Geraghty contractions and investigate the existence and uniqueness of fixed point for the mapping satisfying this condition. We illustrate an example and an application to support our results. In particular, we extend, improve and generalize some earlier results in the literature on this topic.
  • Article
    Citation - WoS: 14
    Citation - Scopus: 24
    Generalized Alpha-Psi Type Mappings of Integral Type and Related Fixed Point Theorems
    (Springer, 2014) Karapinar, Erdal; Shahi, Priya; Tas, Kenan
    The aim of this paper is to introduce two classes of generalized alpha-psi-contractive type mappings of integral type and to analyze the existence of fixed points for these mappings in complete metric spaces. Our results are improved versions of a multitude of relevant fixed point theorems of the existing literature.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 5
    Fixed Point Theorems for Generalized Contractions on gp-metric Spaces
    (Springeropen, 2013) Bilgili, Nurcan; Karapinar, Erdal; Salimi, Peyman
    In this paper, we present two fixed point theorems on mappings, defined on GP-complete GP-metric spaces, which satisfy a generalized contraction property determined by certain upper semi-continuous functions. Furthermore, we illustrate applications of our theorems with a number of examples. Inspired by the work of Jachymski, we also establish equivalences of certain auxiliary maps in the context of GP-complete GP-metric spaces. MSC: 47H10, 54H25.