Tusi Mathematical Research Group (TMRG) and Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with
The Center of Excellence in Analysis on Algebraic Structures)Khayyam Journal of Mathematics2423-47883120170101Stability Results for Neutral Integro-Differential Equations with Multiple Functional Delays1114383110.22034/kjm.2017.43831ENErnest YanksonDepartment of Mathematics and Statistics, University of Cape Coast, Cape
Coast, Ghana.Journal Article20161206Necessary and sufficient conditions for the zero solution of the nonlinear neutral integro-differential equation<br />begin{eqnarray*}<br />&&frac{d}{dt}Big(r(t)Big[x(t)+Q(t, x(t-g_1(t)),...,x(t-g_N(t)))Big]Big)\<br /> &&= -a(t)x(t)+ sum^{N}_{i=1}int^{t}_{t-g_i(t)}k_i(t,s)f_i(x(s))ds<br /> end{eqnarray*}<br /> to be asymptotically stable are obtained. In the process we invert the integro-differential equation and obtain an equivalent integral equation. The contraction mapping principle is used as the main mathematical tool for establishing the necessary and sufficient conditions.Tusi Mathematical Research Group (TMRG) and Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with
The Center of Excellence in Analysis on Algebraic Structures)Khayyam Journal of Mathematics2423-47883120170101Periodic Solutions for Third-Order Nonlinear Delay Differential Equations with Variable Coefficients12214449310.22034/kjm.2017.44493ENAbdelouaheb ArdjouniDepartment of Mathematics and Informatics, University of Souk Ahras, P.O.
Box 1553, Souk Ahras, 41000, Algeria.Farid NouiouaDepartment of Mathematics and Informatics, University of Souk Ahras, P.O.
Box 1553, Souk Ahras, 41000, Algeria.Ahcene DjoudiDepartment of Mathematics, University of Annaba, P.O. Box 12, Annaba,
23000, Algeria.Journal Article20161116In this paper, the following third-order nonlinear delay differential equation<br />with periodic coefficients%<br />begin{align*}<br />& x^{primeprimeprime}(t)+p(t)x^{primeprime}(t)+q(t)x^{prime<br />}(t)+r(t)x(t)\<br />& =fleft( t,xleft( tright) ,x(t-tau(t))right) +frac{d}{dt}gleft(<br />t,xleft( t-tauleft( tright) right) right) ,<br />end{align*}<br />is considered. By employing Green's function, Krasnoselskii's fixed point<br />theorem and the contraction mapping principle, we state and prove the<br />existence and uniqueness of periodic solutions to the third-order nonlinear<br />delay differential equation.Tusi Mathematical Research Group (TMRG) and Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with
The Center of Excellence in Analysis on Algebraic Structures)Khayyam Journal of Mathematics2423-47883120170101Operators Reversing Orthogonality and Characterization of Inner Product Spaces22244474610.22034/kjm.2017.44746ENPaweł WójcikInstitute of Mathematics, Pedagogical University of Cracow, Podchorążych
2, 30-084 Kraków, Poland.Journal Article20170125In this short paper we answer a question posed by Chmieliński in [Adv. Oper. Theory, 1 (2016), no. 1, 8-14].<br /> Namely, we prove that among normed spaces of dimension greater than two,<br />only inner product spaces admit nonzero linear operators which reverse the Birkhoff orthogonality.Tusi Mathematical Research Group (TMRG) and Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with
The Center of Excellence in Analysis on Algebraic Structures)Khayyam Journal of Mathematics2423-47883120170101Certain Properties of a Subclass of Univalent Functions With Finitely Many Fixed Coefficients25324492010.22034/kjm.2017.44920ENS.Sunil VarmaDepartment of Mathematics, Madras Christian College, Tambaram,
Chennai-600059, Tamil Nadu, IndiaThomas RosyDepartment of Mathematics, Madras Christian College, Tambaram,
Chennai-600059, Tamil Nadu, IndiaJournal Article20170111In this paper a new class of analytic, univalent and normalized functions with finitely many fixed coefficients is defined. Properties like coefficient condition, radii of starlikeness and convexity, extreme points and integral operators applied to functions in the class are investigated.Tusi Mathematical Research Group (TMRG) and Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with
The Center of Excellence in Analysis on Algebraic Structures)Khayyam Journal of Mathematics2423-47883120170101On Para-Sasakian Manifolds Satisfying Certain Curvature Conditions with Canonical Paracontact Connection33434519010.22034/kjm.2017.45190ENSelcen Yüksel PerktaşFaculty of Arts and Science, Department of Mathematics, Adıyaman University, Adıyaman, TurkeyJournal Article20160920In this article, the aim is to introduce a para-Sasakian manifold with a<br />canonical paracontact connection. It is shown that $varphi$-conharmonically flat,<br /> $varphi $-$W_{2}$ flat and $varphi $-pseudo projectively flat para-Sasakian manifolds with<br /> respect to canonical paracontact connection are all $eta $-Einstein<br />manifolds. Also, we prove that quasi-pseudo projectively flat<br />para-Sasakian manifolds are of constant scalar curvatures.Tusi Mathematical Research Group (TMRG) and Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with
The Center of Excellence in Analysis on Algebraic Structures)Khayyam Journal of Mathematics2423-47883120170101Approximation for a Summation-Integral Type Link Operators44604532210.22034/kjm.2017.45322ENArun KajlaDepartment of Mathematics, Central University of Haryana, Haryana-123031,
India.Journal Article20170401The present article deals with the general family of summation-integral type operators. Here, we propose the Durrmeyer variant of the generalized <span>Lupaş</span> operators considered by Abel and Ivan (General Math. 15 (1) (2007) 21-34) and study local approximation, Voronovskaja type formula, global approximation, Lipchitz type space and weighted approximation results. Also, we discuss the rate of convergence for absolutely continuous functions having a derivative equivalent with a function of bounded variation.Tusi Mathematical Research Group (TMRG) and Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with
The Center of Excellence in Analysis on Algebraic Structures)Khayyam Journal of Mathematics2423-47883120170101Ostrowski's Inequality for Functions whose First Derivatives are $s$-Preinvex in the Second Sense61804686310.22034/kjm.2017.46863ENBadreddine MeftahLaboratoire des t'el'ecommunications, Facult'e des
Sciences et de la Technologie, University of 8 May 1945 Guelma, P.O. Box
401, 24000 Guelma, Algeria.Journal Article20170402In this paper, we establish some new Ostrowski type inequalities for<br />functions whose first derivatives are $s$-preinvex in the second sense.Tusi Mathematical Research Group (TMRG) and Department of Pure Mathematics, Ferdowsi University of Mashhad (in cooperation with
The Center of Excellence in Analysis on Algebraic Structures)Khayyam Journal of Mathematics2423-47883120170101Proximal Point Algorithms for Numerical Reckoning Fixed Points of Hybrid-Type Multivalued Mappings in Hilbert Spaces81894695110.22034/kjm.2017.46951ENKritsada LerkchaiyaphumDepartment of Mathematics, Faculty of Science and Technology, Nakhon
Pathom Rajabhat University, Nakhon Pathom 73000, Thailand.Withun PhuengrattanaResearch Center for Pure and Applied Mathematics, Research and Development Institute, Nakhon Pathom Rajabhat University, Nakhon Pathom 73000,
Thailand.Journal Article20170330In this paper, we propose a new iteration process to approximate<br />minimizers of proper convex and lower semi-continuous functions and<br />fixed points of $lambda$-hybrid multivalued mappings in Hilbert<br />spaces. We also provide an example to illustrate the convergence<br />behavior of the proposed iteration process and numerically compare<br />the convergence of the proposed iteration scheme with the existing<br />schemes.