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2009

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Strong Convergence Theorems By An Extragradient Method For Solving Variational Inequalities And Equilibrium Problems In A Hilbert Space, Poom Kumam Jan 2009

Strong Convergence Theorems By An Extragradient Method For Solving Variational Inequalities And Equilibrium Problems In A Hilbert Space, Poom Kumam

Turkish Journal of Mathematics

In this paper, we introduce an iterative process for finding the common element of the set of fixed points of a nonexpansive mapping, the set of solutions of an equilibrium problem and the set of solutions of the variational inequality for monotone, Lipschitz-continuous mappings. The iterative process is based on the so-called extragradient method. We show that the sequence converges strongly to a common element of the above three sets under some parametric controlling conditions. This main theorem extends a recent result of Yao, Liou and Yao [Y. Yao, Y. C. Liou and J.-C. Yao, ''An Extragradient Method for Fixed …


Cover And Contents Jan 2009

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


On Symmetric Monomial Curves In P^3, Mesut Şahi̇n Jan 2009

On Symmetric Monomial Curves In P^3, Mesut Şahi̇n

Turkish Journal of Mathematics

In this paper, we give an elementary proof of the fact that symmetric arithmetically Cohen-Macaulay monomial curves are set-theoretic complete intersections. The proof is constructive and provides the equations of the surfaces cutting out the monomial curve.


On \Tau-Lifting Modules And \Tau-Semiperfect Modules, Mustafa Alkan Jan 2009

On \Tau-Lifting Modules And \Tau-Semiperfect Modules, Mustafa Alkan

Turkish Journal of Mathematics

Motivated by [1], we study on \tau-lifting modules (rings) and \tau-semiperfect modules (rings) for a preradical \tau and give some equivalent conditions. We prove that; i) if M is a projective \tau-lifting module with \tau(M) \subseteq \delta(M), then M has the finite exchange property; ii) if R is a left hereditary ring and \tau is a left exact preradical, then every \tau-semiperfect module is \tau--lifting; iii) R is \tau-lifting if and only if every finitely generated free module is \tau-lifting if and only if every finitely generated projective module is \tau-lifting; iv) if \tau (R) \subseteq \delta (R), then R …


The Existence Of Triple Positive Solutions Of Nonlinear Four-Point Boundary Value Problem With P-Laplacian, Xiang-Feng Li, Pei-Hao Zhao Jan 2009

The Existence Of Triple Positive Solutions Of Nonlinear Four-Point Boundary Value Problem With P-Laplacian, Xiang-Feng Li, Pei-Hao Zhao

Turkish Journal of Mathematics

This paper deals with the multiplicity results of positive solutions of one-dimensional singular p-Laplace equation (\varphi_p(u'(t)))'+a(t)f(t,u(t),u'(t))=0, 0


Perturbation Of Closed Range Operators, Mohammad Sal Moslehian, Ghadir Sadeghi Jan 2009

Perturbation Of Closed Range Operators, Mohammad Sal Moslehian, Ghadir Sadeghi

Turkish Journal of Mathematics

Let T, A be operators with domains D(T) \subseteq D(A) in a normed space X. The operator A is called T-bounded if Ax \leq a x +b Tx for some a, b\geq 0 and all x \in D(T). If A has the Hyers--Ulam stability then under some suitable assumptions we show that both T and S: = A+T have the Hyers--Ulam stability. We also discuss the best constant of Hyers--Ulam stability for the operator S. Thus we establish a link between T-bounded operators and Hyers--Ulam stability.


Modified Szász-Mirakjan-Kantorovich Operators Preserving Linear Functions, Oktay Duman, Mehmet Ali̇ Özarslan, Biancamaria Della Vecchia Jan 2009

Modified Szász-Mirakjan-Kantorovich Operators Preserving Linear Functions, Oktay Duman, Mehmet Ali̇ Özarslan, Biancamaria Della Vecchia

Turkish Journal of Mathematics

In this paper, we introduce a modification of the Szász-Mirakjan-Kantorovich operators, which preserve the linear functions. This type of operator modification enables better error estimation on the interval [1/2,+\infty) than the classical Szász-Mirakjan-Kantorovich operators. We also obtain a Voronovskaya-type theorem for these operators.


Equi-Statistical Extension Of The Korovkin Type Approximation Theorem, Sevda Karakuş, Kami̇l Demi̇rci̇ Jan 2009

Equi-Statistical Extension Of The Korovkin Type Approximation Theorem, Sevda Karakuş, Kami̇l Demi̇rci̇

Turkish Journal of Mathematics

In this paper using equi-statistical convergence, which is stronger than the usual uniform convergence and statistical uniform convergence, we obtain a general Korovkin type theorem. Then, we construct examples such that our new approximation result works but its classical and statistical cases do not work.


A New Approach On Constant Angle Surfaces In E^3, Marian Ioan Munteanu, Ana Irina Nistor Jan 2009

A New Approach On Constant Angle Surfaces In E^3, Marian Ioan Munteanu, Ana Irina Nistor

Turkish Journal of Mathematics

In this paper we study constant angle surfaces in Euclidean 3--space. Even that the result is a consequence of some classical results involving the Gauss map (of the surface), we give another approach to classify all surfaces for which the unit normal makes a constant angle with a fixed direction.


Applications Of The Golden Ratio On Riemannian Manifolds, Cristina-Elena Hretcanu, Mircea Craşmareanu Jan 2009

Applications Of The Golden Ratio On Riemannian Manifolds, Cristina-Elena Hretcanu, Mircea Craşmareanu

Turkish Journal of Mathematics

The Golden Ratio is a fascinating topic that continually generates new ideas. The main purpose of the present paper is to point out and find some applications of the Golden Ratio and of Fibonacci numbers in Differential Geometry. We study a structure defined on a class of Riemannian manifolds, called by us a Golden Structure. A Riemannian manifold endowed with a Golden Structure will be called a Golden Riemannian manifold. Precisely, we say that an (1,1)-tensor field \widetilde{P} on a m-dimensional Riemannian manifold (\widetilde{M}, \widetilde{g}) is a Golden Structure if it satisfies the equation \widetilde{P}^{2}=\widetilde{P}+I (which is similar to that …


Cover And Contents Jan 2009

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


Criteria Of Nilpotency And Influence Of Contranormal Subgroups On The Structure Of Infinite Groups, Leonid Andreevich Kurdachenko, Javier Otal, Igor Yakov Subbotin Jan 2009

Criteria Of Nilpotency And Influence Of Contranormal Subgroups On The Structure Of Infinite Groups, Leonid Andreevich Kurdachenko, Javier Otal, Igor Yakov Subbotin

Turkish Journal of Mathematics

Following J.S. Rose, a subgroup H of a group G is called contranormal if G=H^G. In a certain sense, contranormal subgroups are antipodes to subnormal subgroups. It is well known that a finite group is nilpotent if and only if it has no proper contranormal subgroups. However, for infinite groups this criterion is not valid. There are examples of non-nilpotent infinite groups whose subgroups are subnormal; in particular, these groups have no contranormal subgroups. Nevertheless, for some classes of infinite groups, the absence of contranormal subgroups implies nilpotency of the group. The present article is devoted to the search of …


Some Inequalities Concerning The Rate Of Growth Of Polynomials, Abdullah Mir, K. K. Dewan, Naresh Singh Jan 2009

Some Inequalities Concerning The Rate Of Growth Of Polynomials, Abdullah Mir, K. K. Dewan, Naresh Singh

Turkish Journal of Mathematics

In this paper we consider a class of polynomials p(z)=a_0+\suml_{v=t}^n a_vz^v, t\ge1, not vanishing in z


Strong Differential Subordination, Georgia Irina Oros, Gheorghe Oros Jan 2009

Strong Differential Subordination, Georgia Irina Oros, Gheorghe Oros

Turkish Journal of Mathematics

The concept of differential subordination was introduced in [4] by S. S. Miller and P. T. Mocanu and the concept of strong differential subordination was introduced in [1] by J. A. Antonino and S. Romaguera. This last concept was applied in the special case of Briot-Bouquet strong differential subordination. In this paper we study the strong differential subordinations in the general case, following the general theory of differential subordinations presented in [4].


On The Geometry Of Null Curves In The Minkowski 4-Space, Recep Aslaner, A. İhsan Boran Jan 2009

On The Geometry Of Null Curves In The Minkowski 4-Space, Recep Aslaner, A. İhsan Boran

Turkish Journal of Mathematics

In this paper, we study the basic results on the general study of null curves in the Minkowski 4-space R_1^4. A transversal vector bundle of a null curve in R_1^4 is constructed using a frenet Frame consisting of two real null and two space-like vectors. The null curves are characterized by using the Frenet frame.


Approximation By Certain Linear Operators Preserving X^2, Lucyna Rempulska, Karolina Tomczak Jan 2009

Approximation By Certain Linear Operators Preserving X^2, Lucyna Rempulska, Karolina Tomczak

Turkish Journal of Mathematics

We investigate certain positive linear operators L_n preserving the functions e_k (x)=x^k, k=0, 1, and modified operators L_n^* which preserve e_0 and e_2. We show that the error of approximation of f by L_n^* (f) is smaller than for L_n(f).


Partial Open Book Decompositions And The Contact Class In Sutured Floer Homology, Tolga Etgü, Burak Özbağci Jan 2009

Partial Open Book Decompositions And The Contact Class In Sutured Floer Homology, Tolga Etgü, Burak Özbağci

Turkish Journal of Mathematics

We demonstrate how to combinatorially calculate the EH-class of a compatible contact structure in the sutured Floer homology group of a balanced sutured three manifold which is associated to an abstract partial open book decomposition. As an application we show that every contact three manifold (closed or with convex boundary) can be obtained by gluing tight contact handlebodies whose EH-classes are nontrivial.


Cover And Contents Jan 2009

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


Uniqueness For Meromorphic Functions And Differential Polynomials, Chao Meng Jan 2009

Uniqueness For Meromorphic Functions And Differential Polynomials, Chao Meng

Turkish Journal of Mathematics

In this article, we deal with the uniqueness problems on meromorphic functions concerning differential polynomials and prove the following result: Let f and g be two transcendental meromorphic functions, \alpha be a meromorphic function such that T(r,\alpha)=o(T(r,f)+T(r,g)) and \alpha \not\equiv 0,\infty. Let a be a nonzero constant. Suppose that m,n are positive integers such that n>m+10. If \Psi_f' and \Psi_g' share ``(0,2)", then (i) if m\geq 2, then f(z)\equiv g(z); (ii) if m=1, either f(z)\equiv g(z) or f and g satisfy the algebraic equation R(f,g)\equiv 0, where R(\varpi_1,\varpi_2)=(n+1)(\varpi_1^{n+2}-\varpi_2^{n+2})-(n+2)(\varpi_1^{n+1} -\varpi_2^{n+1}). The results in this paper improve the results of Xiong-Lin-Mori …


C1 Modules With Respect To A Hereditary Torsion Theory, Tahi̇re Özen Jan 2009

C1 Modules With Respect To A Hereditary Torsion Theory, Tahi̇re Özen

Turkish Journal of Mathematics

An R-module M is said to be a C1-module if every closed submodule of M is a direct summand. In this paper we introduce and investigate the concept of the \tau-C1 module for a hereditary torsion theory \tau on Mod-R. \tau-C1 modules are a generalization of C1-modules.


Oscillation Of Nonlinear Neutral Delay Differential Equations Of Second-Order With Positive And Negative Coefficients, Mustafa Kemal Yildiz, Başak Karpuz, Özkan Öcalan Jan 2009

Oscillation Of Nonlinear Neutral Delay Differential Equations Of Second-Order With Positive And Negative Coefficients, Mustafa Kemal Yildiz, Başak Karpuz, Özkan Öcalan

Turkish Journal of Mathematics

Some oscillation criteria for the following second-order neutral differential equation [x(t)\pm r(t) f( x(t-\gamma))]''+p(t) g(x(t-\alpha)) -q(t) g(x(t-\beta )) = s(t) where t\geq t_0, \gamma,\alpha,\beta \in R^+ with \alpha \geq \beta, r \in C^2([t_0,\infty ), R^+) , p,q\in C([t_0,\infty ),R^+) and f,g\in C(R,R), s\in C([ t_0,\infty),R) have been obtained. Our results are not restricted with boundedness of solutions.


Some Properties Of The First Eigenvalue Of The $P(X)$-Laplacian On Riemannian Manifolds, R. A. Mashiyev, Guli̇zar Ali̇soy, Sezai̇ Ogras Jan 2009

Some Properties Of The First Eigenvalue Of The $P(X)$-Laplacian On Riemannian Manifolds, R. A. Mashiyev, Guli̇zar Ali̇soy, Sezai̇ Ogras

Turkish Journal of Mathematics

The main result of the present paper establishes a stability property of the first eigenvalue of the associated problem which deals with the $p(x)$-Laplacian on Riemannian manifolds with Dirichlet boundary condition.


Solutions For 2n^{Th} Order Lidstone Bvp On Time Scales, Erbi̇l Çeti̇n, S. Gülşan Topal Jan 2009

Solutions For 2n^{Th} Order Lidstone Bvp On Time Scales, Erbi̇l Çeti̇n, S. Gülşan Topal

Turkish Journal of Mathematics

In this paper, we prove the existence of solutions for nonlinear Lidstone boundary value problems by using the monotone method on time scale and also we show the existence of at least one positive solution if f is either superlinear or sublinear by the fixed point theorem in a Banach space.


A Perturbation Of M-Order Derivations On Banach Algebras, Yong-Soo Jung, Kyoo-Hong Park Jan 2009

A Perturbation Of M-Order Derivations On Banach Algebras, Yong-Soo Jung, Kyoo-Hong Park

Turkish Journal of Mathematics

Let \A be a unital Banach algebra and let m, 1 \leq m \leq 4, be an integer. If f: \A \to \A is an approximate m-order derivation in the sense of Hyers-Ulam-Rassias, then f: \A \to \A is an exact m-order derivation.


On Completeness Of Elementary Generalized Solutions Of A Class Of Operator-Differential Equations Of A Higher Order, Rovshan Z. Gumbataliev Jan 2009

On Completeness Of Elementary Generalized Solutions Of A Class Of Operator-Differential Equations Of A Higher Order, Rovshan Z. Gumbataliev

Turkish Journal of Mathematics

In this paper we give definition of m-fold completeness and prove a theorem on completeness of elementary generalized solution of corresponding boundary value problems at which the equation describes the process of corrosive fracture of metals in aggressive media and the principal part of the equation has multiple characteristics.


Intrinsic Equations For A Generalized Relaxed Elastic Line On An Oriented Surface In The Minkowski 3-Space E_1^3, Cumali̇ Eki̇ci̇, Ali̇ Görgülü Jan 2009

Intrinsic Equations For A Generalized Relaxed Elastic Line On An Oriented Surface In The Minkowski 3-Space E_1^3, Cumali̇ Eki̇ci̇, Ali̇ Görgülü

Turkish Journal of Mathematics

H. K. Nickerson and Gerald S. Manning [8] derived the intrinsic equations for a relaxed elastic line on an oriented surface in the Euclidean 3-dimensional space E^3. In this paper, we define a generalized relaxed elastic line and derive the intrinsic equations for a generalized of relaxed elastic line on an oriented surface in the Minkowski 3-dimensional space E_1^3 and give some applications of the result.


Cover And Contents Jan 2009

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


Accurate Prediction Of Crosstalk For Rc Interconnects, Selahatti̇n Sayil, Merlyn Rudrapati Jan 2009

Accurate Prediction Of Crosstalk For Rc Interconnects, Selahatti̇n Sayil, Merlyn Rudrapati

Turkish Journal of Electrical Engineering and Computer Sciences

This work proposes an accurate crosstalk noise estimation method in the presence of multiple RC lines for use in design automation tools. The method correctly models the loading effects of non switching aggressors and aggressor tree branches using resistive shielding effect and realistic exponential input waveform. Noise peak and width expressions derived show very good results in comparison to HSPICE results. Results show that average error for noise peak is 4.1% and for the width is 6.8% while allowing for very fast analysis.


Voltage Control Of Self-Excited Induction Generator Using Genetic Algorithm, Dheeraj Joshi, Kanwarjit Singh Sandhu, Mahender Kumar Soni Jan 2009

Voltage Control Of Self-Excited Induction Generator Using Genetic Algorithm, Dheeraj Joshi, Kanwarjit Singh Sandhu, Mahender Kumar Soni

Turkish Journal of Electrical Engineering and Computer Sciences

Self-excited induction generators (SEIG) are found to be most suitable candidate for wind energy conversion application required at remote windy locations. Such generators are not able to maintain the terminal voltage with load as, a literature survey reveals, the voltage profile falls sharply with load. In this paper an attempt has been made to improve the voltage profile of a self-excited induction generator. A new methodology based upon Genetic Algorithm (GA) is proposed to compute the steady state performance of the model including core loss branch. Further efforts are made to control the terminal voltage under loaded conditions. Simulated results …


Electronic Differential With Direct Torque Fuzzy Control For Vehicle Propulsion System, Kada Hartani, Mohamed Bourahla, Yahia Miloud, Mohamed Sekour Jan 2009

Electronic Differential With Direct Torque Fuzzy Control For Vehicle Propulsion System, Kada Hartani, Mohamed Bourahla, Yahia Miloud, Mohamed Sekour

Turkish Journal of Electrical Engineering and Computer Sciences

We model an electronic differential that will offer the best vehicle stability on a curved road. The proposed traction system consists of two permanent magnet synchronous (PMS) machines that ensure the drive of two back-driving wheels. The contribution of each wheel to the advance of the vehicle is represented by an element conveying the accumulation of mechanical coupling. The proposed control structure is based on the direct torque fuzzy control for each wheel-motor. Different simulations have been carried out: vehicle driven ons straight road, vehicle driven on straight road with slope, and vehicle driven over a road curved left and …