Stability Results for Neutral Integro-Differential Equations with Multiple Functional Delays
Ernest
Yankson
Department of Mathematics and Statistics, University of Cape Coast, Cape
Coast, Ghana.
author
text
article
2017
eng
Necessary and sufficient conditions for the zero solution of the nonlinear neutral integro-differential equation\begin{eqnarray*}&&\frac{d}{dt}\Big(r(t)\Big[x(t)+Q(t, x(t-g_1(t)),...,x(t-g_N(t)))\Big]\Big)\\ &&= -a(t)x(t)+ \sum^{N}_{i=1}\int^{t}_{t-g_i(t)}k_i(t,s)f_i(x(s))ds \end{eqnarray*} 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.
Khayyam Journal of Mathematics
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)
2423-4788
3
v.
1
no.
2017
1
11
http://www.kjm-math.org/article_43831_2161050be631ca19a702fe6a0bd6d1c3.pdf
dx.doi.org/10.22034/kjm.2017.43831
Periodic Solutions for Third-Order Nonlinear Delay Differential Equations with Variable Coefficients
Abdelouaheb
Ardjouni
Department of Mathematics and Informatics, University of Souk Ahras, P.O.
Box 1553, Souk Ahras, 41000, Algeria.
author
Farid
Nouioua
Department of Mathematics and Informatics, University of Souk Ahras, P.O.
Box 1553, Souk Ahras, 41000, Algeria.
author
Ahcene
Djoudi
Department of Mathematics, University of Annaba, P.O. Box 12, Annaba,
23000, Algeria.
author
text
article
2017
eng
In this paper, the following third-order nonlinear delay differential equationwith periodic coefficients%\begin{align*}& x^{\prime\prime\prime}(t)+p(t)x^{\prime\prime}(t)+q(t)x^{\prime}(t)+r(t)x(t)\\& =f\left( t,x\left( t\right) ,x(t-\tau(t))\right) +\frac{d}{dt}g\left(t,x\left( t-\tau\left( t\right) \right) \right) ,\end{align*}is considered. By employing Green's function, Krasnoselskii's fixed pointtheorem and the contraction mapping principle, we state and prove theexistence and uniqueness of periodic solutions to the third-order nonlineardelay differential equation.
Khayyam Journal of Mathematics
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)
2423-4788
3
v.
1
no.
2017
12
21
http://www.kjm-math.org/article_44493_fca28ec0388a064bcfebffd47c16b12f.pdf
dx.doi.org/10.22034/kjm.2017.44493
Operators Reversing Orthogonality and Characterization of Inner Product Spaces
Paweł
Wójcik
Institute of Mathematics, Pedagogical University of Cracow, Podchorążych
2, 30-084 Kraków, Poland.
author
text
article
2017
eng
In this short paper we answer a question posed by Chmieliński in [Adv. Oper. Theory, 1 (2016), no. 1, 8-14]. Namely, we prove that among normed spaces of dimension greater than two,only inner product spaces admit nonzero linear operators which reverse the Birkhoff orthogonality.
Khayyam Journal of Mathematics
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)
2423-4788
3
v.
1
no.
2017
22
24
http://www.kjm-math.org/article_44746_9f829bbb7fc2df9483fd2622f9084732.pdf
dx.doi.org/10.22034/kjm.2017.44746
Certain Properties of a Subclass of Univalent Functions With Finitely Many Fixed Coefficients
S.Sunil
Varma
Department of Mathematics, Madras Christian College, Tambaram,
Chennai-600059, Tamil Nadu, India
author
Thomas
Rosy
Department of Mathematics, Madras Christian College, Tambaram,
Chennai-600059, Tamil Nadu, India
author
text
article
2017
eng
In 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.
Khayyam Journal of Mathematics
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)
2423-4788
3
v.
1
no.
2017
25
32
http://www.kjm-math.org/article_44920_245bef22255f8b0b38f19d4c0c83a25b.pdf
dx.doi.org/10.22034/kjm.2017.44920
On Para-Sasakian Manifolds Satisfying Certain Curvature Conditions with Canonical Paracontact Connection
Selcen
Yüksel Perktaş
Faculty of Arts and Science, Department of Mathematics, Adıyaman University, Adıyaman, Turkey
author
text
article
2017
eng
In this article, the aim is to introduce a para-Sasakian manifold with acanonical paracontact connection. It is shown that $\varphi$-conharmonically flat, $\varphi $-$W_{2}$ flat and $\varphi $-pseudo projectively flat para-Sasakian manifolds with respect to canonical paracontact connection are all $\eta $-Einsteinmanifolds. Also, we prove that quasi-pseudo projectively flatpara-Sasakian manifolds are of constant scalar curvatures.
Khayyam Journal of Mathematics
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)
2423-4788
3
v.
1
no.
2017
33
43
http://www.kjm-math.org/article_45190_7d44a17d67db3000195bfd95cc73a650.pdf
dx.doi.org/10.22034/kjm.2017.45190
Approximation for a Summation-Integral Type Link Operators
Arun
Kajla
Department of Mathematics, Central University of Haryana, Haryana-123031,
India.
author
text
article
2017
eng
The present article deals with the general family of summation-integral type operators. Here, we propose the Durrmeyer variant of the generalized Lupaş 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.
Khayyam Journal of Mathematics
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)
2423-4788
3
v.
1
no.
2017
44
60
http://www.kjm-math.org/article_45322_725917aec0e6b1c459fe81fc2e4d7411.pdf
dx.doi.org/10.22034/kjm.2017.45322
Ostrowski's Inequality for Functions whose First Derivatives are $s$-Preinvex in the Second Sense
Badreddine
Meftah
Laboratoire 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.
author
text
article
2017
eng
In this paper, we establish some new Ostrowski type inequalities forfunctions whose first derivatives are $s$-preinvex in the second sense.
Khayyam Journal of Mathematics
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)
2423-4788
3
v.
1
no.
2017
61
80
http://www.kjm-math.org/article_46863_69c7dd0b531fa53298dd16c90cd3a0f8.pdf
dx.doi.org/10.22034/kjm.2017.46863
Proximal Point Algorithms for Numerical Reckoning Fixed Points of Hybrid-Type Multivalued Mappings in Hilbert Spaces
Kritsada
Lerkchaiyaphum
Department of Mathematics, Faculty of Science and Technology, Nakhon
Pathom Rajabhat University, Nakhon Pathom 73000, Thailand.
author
Withun
Phuengrattana
Research Center for Pure and Applied Mathematics, Research and Development Institute, Nakhon Pathom Rajabhat University, Nakhon Pathom 73000,
Thailand.
author
text
article
2017
eng
In this paper, we propose a new iteration process to approximateminimizers of proper convex and lower semi-continuous functions andfixed points of $\lambda$-hybrid multivalued mappings in Hilbertspaces. We also provide an example to illustrate the convergencebehavior of the proposed iteration process and numerically comparethe convergence of the proposed iteration scheme with the existingschemes.
Khayyam Journal of Mathematics
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)
2423-4788
3
v.
1
no.
2017
81
89
http://www.kjm-math.org/article_46951_9c228d2ed70ca44facd3ac48e7b8797e.pdf
dx.doi.org/10.22034/kjm.2017.46951