WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article Citation - WoS: 19Citation - Scopus: 18Best Proximity Point Theorems for Kt-Types Cyclic Orbital Contraction Mappings(House Book Science-casa Cartii Stiinta, 2012) Karapınar, Erdal; Karapinar, Erdal; Petrusel, Gabriela; Taş, Kenan; Tas, Kenan; MatematikIn this manuscript, three new KT-types cyclic orbital contractions are defined and some related best proximity point theorems are given. Also, the notion of KT-type cyclic orbital Meir-Keeler contraction is defined and some fixed point theorems for this class of mappings are proved. The results of this manuscript generalize some theorems, on the same subject, of several authors, such as Kirk-Srinavasan-Veeramani, Eldered-Veeramani and Karpagam-Agrawal.Article Citation - WoS: 16Citation - Scopus: 22Some Fixed Point Results for Tac-Type Contractive Mappings(Hindawi Ltd, 2016) Tas, Kenan; Ansari, Arslan Hojat; Chandok, SumitWe prove some fixed point results for new type of contractive mappings using the notion of cyclic admissible mappings in the framework of metric spaces. Our results extend, generalize, and improve some well-known results from literature. Some examples are given to support our main results.Article Citation - WoS: 2Citation - Scopus: 1Coupled Common Fixed Point Results Involving (φ,ψ)-Contractions in Ordered Generalized Metric Spaces With Application To Integral Equations(Springeropen, 2013) Tas, Kenan; Gupta, Neetu; Jain, ManishWe establish some coupled coincidence and coupled common fixed point theorems for the mixed g-monotone mappings satisfying -contractive conditions in the setting of ordered generalized metric spaces. Presented theorems extend and generalize the very recent results of Choudhury and Maity (Math. Comput. Model. 54(1-2):73-79, 2011). To illustrate our results, an example and an application to integral equations have also been given. MSC: 54H10, 54H25.Article Citation - WoS: 59Citation - Scopus: 68Generalized (c)-Conditions and Related Fixed Point Theorems(Pergamon-elsevier Science Ltd, 2011) Karapinar, Erdal; Tas, KenanIn this manuscript, the notion of C-condition [K. Suzuki, Fixed point theorems and convergence theorems for some generalized nonexpansive mappings, J. Math. Anal. Appl. 340 (2008) 1088-1095] is generalized. Some new fixed point theorems are obtained. (C) 2011 Elsevier Ltd. All rights reserved.Article Coupled Fixed Points in Complex Partial Metric Spaces(int Scientific Research Publications, 2022) Khan, M. S.; Singh, Y. Mahendra; Tas, Kenan; Gunaseelan, M.In this paper, we obtain coupled fixed point theorems in complex partial metric spaces under the different contractive conditions. Examples are provided to support our results.Article Citation - WoS: 7Citation - Scopus: 10Common Fixed Point Theorems for Generalized (φ,ψ)-Weak Contraction Condition in Complete Metric Spaces(Springer international Publishing Ag, 2015) Tas, Kenan; Patel, Uma Devi; Murthy, Penumarthy ParvateesamThe intent of this manuscript is to establish some common fixed point theorems in a complete metric space under weak contraction condition for two pairs of discontinuous weak compatible maps. The results proved herein are the generalization of some recent results in literature. We give an example to support our results.Article Citation - WoS: 6Citation - Scopus: 6The Radii of Sections of Origin-Symmetric Convex Bodies and Their Applications(Academic Press inc Elsevier Science, 2021) Tas, Kenan; Kushpel, AlexanderLet V and W be any convex and origin-symmetric bodies in R-n . Assume that for some A is an element of L (R-n -> R-n), det A not equal 0, V is contained in the ellipsoid A(-1)B((2))(n), where B-(2)(n) is the unit Euclidean ball. We give a lower bound for the W-radius of sections of A(-1) V in terms of the spectral radius of AA and the expectations of parallel to . parallel to(V) and parallel to . parallel to(W)0 with respect to Haar measure on Sn-1 subset of R-n. It is shown that the respective expectations are bounded as n -> infinity in many important cases. As an application we offer a new method of evaluation of n-widths of multiplier operators. As an example we establish sharp orders of n-widths of multiplier operators Lambda : L-p (M-d) -> L-q (M-d), 1 < q <= 2 <= p < infinity on compact homogeneous Riemannian manifolds M-d. Also, we apply these results to prove the existence of flat polynomials on M-d. (c) 2020 Elsevier Inc. All rights reserved.Article Further Results on the Neutrix Composition of Distributions Involving the Delta Function and the Function Cosh+<sup>-1</Sup> (x<sup>1/R<(de Gruyter Poland Sp Z O O, 2019) Tas, Kenan; Fisher, BrianThe neutrix composition F(f(x)) of a distribution F(x) and a locally summable function f(x) is said to exist and be equal to the distribution h(x) if the neutrix limit of the sequence {F-n(f(x))) is equal to h(x), where F-n(x) = F(x) * delta(n)(x) and {delta(n)(x)} is a certain sequence of infinitely differentiable functions converging to the Dirac delta-function delta(x). The function cosh(+)(-1)(x + 1) is defined by cosh(+)(-1)(x+ 1) = H(x) cosh(-1)(vertical bar x vertical bar + 1), where H(x) denotes Heaviside's function. It is then proved that the neutrix composition delta((s))[cosh(+)(-1)(x(1/r) + 1)] exists and delta((s))[cosh(+)(-1)(x(1/r) + 1] = Sigma(s-1)(k=0) Sigma(kr+r-1)(j=0) Sigma(j)(i=0) (-1)(kr+r+s-j-1)r/2(j+2) ((kr + r -1)(j)) ((j)(i)) [(j - 2i + 1)(s) - (j - 2i -1)(s)]delta((k))(x) for r, s = 1, 2, .... Further results are also proved. Our results improve, extend and generalize the main theorem of [Fisher B., Al-Sirehy F., Some results on the neutrix composition of distributions involving the delta function and the function cosh(+)(-1) (x + 1), Appl. Math. Sci. (Ruse), 2014, 8(153), 7629-7640].Article Citation - WoS: 7Citation - Scopus: 13Approximate Controllability of Infinite-Dimensional Degenerate Fractional Order Systems in the Sectorial Case(Mdpi, 2019) Gordievskikh, Dmitriy M.; Tas, Kenan; Baleanu, Dumitru; Fedorov, Vladimir E.We consider a class of linear inhomogeneous equations in a Banach space not solvable with respect to the fractional Caputo derivative. Such equations are called degenerate. We study the case of the existence of a resolving operators family for the respective homogeneous equation, which is an analytic in a sector. The existence of a unique solution of the Cauchy problem and of the Showalter-Sidorov problem to the inhomogeneous degenerate equation is proved. We also derive the form of the solution. The approximate controllability of infinite-dimensional control systems, described by the equations of the considered class, is researched. An approximate controllability criterion for the degenerate fractional order control system is obtained. The criterion is illustrated by the application to a system, which is described by an initial-boundary value problem for a partial differential equation, not solvable with respect to the time-fractional derivative. As a corollary of general results, an approximate controllability criterion is obtained for the degenerate fractional order control system with a finite-dimensional input.Article Citation - WoS: 6Citation - Scopus: 6On Square Integrable Solutions of a Fractional Differential Equation(Elsevier Science inc, 2018) Ugurlu, Ekin; Baleanu, Dumitru; Tas, KenanIn this paper we construct the Weyl-Titchmarsh theory for the fractional Sturm-Liouville equation. For this purpose we used the Caputo and Riemann-Liouville fractional operators having the order is between zero and one. (C) 2018 Elsevier Inc. All rights reserved.