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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: 176
    Citation - Scopus: 196
    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: 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.
  • Article
    Citation - WoS: 57
    Citation - Scopus: 75
    Further Fixed Point Results on g-metric Spaces
    (Springer int Publ Ag, 2013) Karapinar, Erdal; Agarwal, Ravi P.
    Very recently, Samet et al. (Int. J. Anal. 2013: 917158, 2013) and Jleli-Samet (Fixed Point Theory Appl. 2012: 210, 2012) noticed that some fixed point theorems in the context of a G-metric space can be deduced by some well-known results in the literature in the setting of a usual (quasi) metric space. In this paper, we note that the approach of Samet et al. (Int. J. Anal. 2013: 917158, 2013) and Jleli-Samet (Fixed Point Theory Appl. 2012: 210, 2012) is inapplicable unless the contraction condition in the statement of the theorem can be reduced into two variables. For this purpose, we modify some existing results to suggest new fixed point theorems that fit with the nature of a G-metric space. The expressions in our result, the contraction condition, cannot be expressed in two variables, therefore the techniques used in (Int. J. Anal. 2013: 917158, 2013; Fixed Point Theory Appl. 2012: 210, 2012) are not applicable.
  • Article
    Citation - WoS: 61
    Citation - Scopus: 81
    Dislocated metric space to metric spaces with some fixed point theorems
    (Springer international Publishing Ag, 2013) Karapinar, Erdal; Salimi, Peyman
    In this paper, we notice the notions metric-like space and dislocated metric space are exactly the same. After this historical remark, we discuss the existence and uniqueness of a fixed point of a cyclic mapping in the context of metric-like spaces. We consider some examples to illustrate the validity of the derived results of this paper.
  • Article
    Citation - WoS: 60
    Citation - Scopus: 72
    Remarks on some coupled fixed point theorems in G-metric spaces
    (Springer international Publishing Ag, 2013) Agarwal, Ravi P.; Karapinar, Erdal
    In this paper, we show that, unexpectedly, most of the coupled fixed point theorems in the context of (ordered) G-metric spaces are in fact immediate consequences of usual fixed point theorems that are either well known in the literature or can be obtained easily.
  • Article
    Citation - WoS: 57
    Citation - Scopus: 71
    Fixed Point Theorems for Α-Geraghty Contraction Type Maps in Metric Spaces
    (Springer int Publ Ag, 2013) Cho, Seong-Hoon; Bae, Jong-Sook; Karapinar, Erdal
    In this paper, we introduce a notion of alpha-Geraghty contraction type maps in the setting of a metric space. We also establish some fixed point theorems for such maps and give an example to illustrate our results. Finally, we discuss the application of our main results in the research fields of ordinary differential equations.
  • 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: 4
    Citation - Scopus: 4
    Fixed Point Theorems for Generalized Weak Contractions Satisfying Rational Expression on a Ordered Partial Metric Space
    (Maik Nauka/interperiodica/springer, 2013) Karapinar, Erdal; Marudai, M.; Pragadeeswarar, V.
    The purpose of this manuscript is to present a fixed point theorem using a generalized weak contraction condition of rational type in the context of partial metric spaces.