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2010

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Articles 601 - 630 of 690

Full-Text Articles in Mathematics

On Orders And Types Of Dirichlet Series Of Slow Growth, Yinying Kong, Huilin Gan Jan 2010

On Orders And Types Of Dirichlet Series Of Slow Growth, Yinying Kong, Huilin Gan

Turkish Journal of Mathematics

The present paper has the object of showing some interesting relationship on the maximum modulus, the maximum term, the index of maximum term and the coefficients of entire functions defined by Dirichlet series of slow growth; some properties like Taylor entire functions are obtained.

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Sufficient Conditions For Univalence Obtained By Using Second Order Linear Strong Differential Subordinations, Georgia Irina Oros Jan 2010

Sufficient Conditions For Univalence Obtained By Using Second Order Linear Strong Differential Subordinations, Georgia Irina Oros

Turkish Journal of Mathematics

The concept of differential subordination was introduced in [3] by S.S. Miller and P.T. Mocanu and the concept of strong differential subordination was introduced in [1], [2] by J.A. Antonino and S. Romaguera. In [5] we have studied the strong differential subordinations in the general case and in [6] we have studied the first order linear strong differential subordinations. In this paper we study the second order linear strong differential subordinations. Our results may be applied to deduce sufficient conditions for univalence in the unit disc, such as starlikeness, convexity, alpha-convexity, close-to-convexity respectively.

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Uniqueness Of Derivatives Of Meromorphic Functions Sharing Two Or Three Sets, Abhijit Banerjee, Pranab Bhattacharjee Jan 2010

Uniqueness Of Derivatives Of Meromorphic Functions Sharing Two Or Three Sets, Abhijit Banerjee, Pranab Bhattacharjee

Turkish Journal of Mathematics

In the paper we consider the problem of uniqueness of derivatives of meromorphic functions when they share two or three sets and obtained five results which will improve all the existing results.

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Nontrivial Periodic Solutions Of Nonlinear Functional Differential Systems With Feedback Control, Yingxin Guo Jan 2010

Nontrivial Periodic Solutions Of Nonlinear Functional Differential Systems With Feedback Control, Yingxin Guo

Turkish Journal of Mathematics

This paper examines the existence of nontrivial periodic solutions for the nonlinear functional differential system with feedback control: \{\aligned x'(t)=x(t)a(t)-\big[\sum_{i=1}^n a_i(t)\int_0^{+\infty} f(t, x(t-\theta)) d}\varphi_i(\theta) +\sum_{j=1}^m b_j(t) \int_0^{+\infty} f(t,x'(t-\theta))\,d}\phi_j(\theta)+\sum_{\mu=1}^p c_\mu(t) \int_0^{\infty} u(t-\theta)\,d}\delta_\mu(\theta)\big], u'(t)=-\rho(t)u(t)+\sum_{\nu=1}^q \beta_\nu(t) \int_0^{\infty} f(t, x(t-\theta))\,d}\psi_\nu(\theta).\endaligned Under certain growth conditions on the nonlinearity f, several sufficient conditions for the existence of nontrivial solution are obtained by using Leray-Schauder nonlinear alternative.

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Existence And Uniqueness Of Solutions To Neutral Stochastic Functional Differential Equations With Infinite Delay In L^P(\Omega,C_H), Haibo Bao Jan 2010

Existence And Uniqueness Of Solutions To Neutral Stochastic Functional Differential Equations With Infinite Delay In L^P(\Omega,C_H), Haibo Bao

Turkish Journal of Mathematics

In this paper, we shall consider the existence and uniqueness of solutions to neutral stochastic functional differential equations with infinite delay in L^p(\Omega,C_h) space: d[x(t)-G(x_t)]=f(t,x_t)dt+g(t,x_t)dB(t), where we assume f:R^+\times L^p(\Omega,C_h) \to L^p(\Omega,R^n), g:R^+\times L^p(\Omega,C_h) \to L^p(\Omega,L(R^m, R^n)), G: L^p(\Omega,C_h) \to L^p(\Omega,R^n), p>2,\, and B(t) is a given m-dimensional Brownian motion.

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On Maximum Principle And Existence Of Positive Weak Solutions For N\Times N Nonlinear Elliptic Systems Involving Degenerated P-Laplacian Operators, H. M. Serag, S. A. Khafagy Jan 2010

On Maximum Principle And Existence Of Positive Weak Solutions For N\Times N Nonlinear Elliptic Systems Involving Degenerated P-Laplacian Operators, H. M. Serag, S. A. Khafagy

Turkish Journal of Mathematics

We study the Maximum Principle and existence of positive weak solutions for the n \times n nonlinear elliptic system -\Delta_{P,p}u_i=\sum_{j=1}^na_{ij}(x) u_j ^{p-2}u_j+f_i(x,u_1,u_2, ... ,u_n) in \Omega, u_i=0,\ i=1,2,. n on \partial \Omega \} where the degenerated p-Laplacian defined as \Delta _{P,p}u=div [P(x) \nabla u ^{p-2}\nabla u] with p>1,p \neq 2 and P(x) is a weight function. We give some conditions for having the Maximum Principle for this system and then we prove the existence of positive weak solutions for the quasilinear system by using ``sub-super solutions method''.

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Korovkin Type Approximation Theorem For Functions Of Two Variables In Statistical Sense, Fadi̇me Di̇ri̇k, Kami̇l Demi̇rci̇ Jan 2010

Korovkin Type Approximation Theorem For Functions Of Two Variables In Statistical Sense, Fadi̇me Di̇ri̇k, Kami̇l Demi̇rci̇

Turkish Journal of Mathematics

In this paper, using the concept of A-statistical convergence for double sequences, we investigate a Korovkin-type approximation theorem for sequences of positive linear operator on the space of all continuous real valued functions defined on any compact subset of the real two-dimensional space. Then we display an application which shows that our new result is stronger than its classical version. We also obtain a Voronovskaya-type theorem \ and some differential properties for sequences of positive linear operators constructed by means of the Bernstein polynomials of two variables.

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A Gap Theorem For Complete Space-Like Hypersurface With Constant Scalar Curvature In Locally Symmetric Lorentz Spaces, Jiancheng Liu, Lin Wei Jan 2010

A Gap Theorem For Complete Space-Like Hypersurface With Constant Scalar Curvature In Locally Symmetric Lorentz Spaces, Jiancheng Liu, Lin Wei

Turkish Journal of Mathematics

Let M^n be a complete space-like hypersurface with constant scalar curvature in locally symmetric Lorentz space N^{n+1}_1, S be the squared norm of the second fundamental form of M^n in N^{n+1}_1. In this paper, we obtain a gap property of S: if nP\leq \sup S\leq D(n,P) for some constants P and D(n, P), then either \sup S=nP and M^n is totally umbilical, or \sup S=D(n, P) and M^n has two distinct principal curvatures.

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B.-Y. Chen Inequalities For Slant Submanifolds In Quaternionic Space Forms, Gabriel Eduard Vilcu Jan 2010

B.-Y. Chen Inequalities For Slant Submanifolds In Quaternionic Space Forms, Gabriel Eduard Vilcu

Turkish Journal of Mathematics

In this paper some B.-Y. Chen inequalities for slant submanifolds in quaternionic space forms are established.

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Extremal Lagrangian Submanifolds In A Complex Space Form N^N(4c), Shichang Shu, Annie Yi Han Jan 2010

Extremal Lagrangian Submanifolds In A Complex Space Form N^N(4c), Shichang Shu, Annie Yi Han

Turkish Journal of Mathematics

Let N^n(4c) be the complex space form of constant holomorphic sectional curvature 4c, \varphi: M \to N^n(4c) be an immersion of an n-dimensional Lagrangian manifold M in N^n(4c). Denote by S and H the square of the length of the second fundamental form and the mean curvature of M. Let \rho be the non-negative function on M defined by \rho^2=S-nH^2, Q be the function which assigns to each point of M the infimum of the Ricci curvature at the point. In this paper, we consider the variational problem for non-negative functional U(\varphi)=\int_M\rho^2dv=\int_M(S-nH^2)dv. We call the critical points of U(\varphi) the …

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A Note On The Lyapunov Exponent In Continued Fraction Expansions, Jianzhong Cheng, Lu-Ming Shen Jan 2010

A Note On The Lyapunov Exponent In Continued Fraction Expansions, Jianzhong Cheng, Lu-Ming Shen

Turkish Journal of Mathematics

Let T:[0,1) \to [0,1) be the Gauss transformation. For any irrational x \in [0,1), the Lyapunov exponent \alpha(x) of x is defined as \alpha(x)=\lim_{n\to\infty}\frac{1}{n} \log (T^n)'(x) . By Birkoff Average Theorem, one knows that \alpha(x) exists almost surely. However, in this paper, we will see that the non-typical set \{x\in [0,1):\lim_{n\to\infty}\frac{1}{n} \log (T^n)'(x) does not exist\} carries full Hausdorff dimension.

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The Riemann Hilbert Problem For Generalized Q-Holomorphic Functions, Sezayi̇ Hizliyel, Mehmet Çağliyan Jan 2010

The Riemann Hilbert Problem For Generalized Q-Holomorphic Functions, Sezayi̇ Hizliyel, Mehmet Çağliyan

Turkish Journal of Mathematics

In this work, the classical Riemann Hilbert boundary value problem is extended to generalized Q-holomorphic functions.

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The Principal Eigencurves For A Nonselfadjoint Elliptic Operator, Aomar Anane, Omar Chakrone, Abdellah Zerouali Jan 2010

The Principal Eigencurves For A Nonselfadjoint Elliptic Operator, Aomar Anane, Omar Chakrone, Abdellah Zerouali

Turkish Journal of Mathematics

In this paper we study the existence of the principal eigencurves for a nonselfadjoint elliptic operator. We obtain their variational formulation. We establish also the continuity and the differentiability of the principal eigencurves.

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Direct And Inverse Theorems For The Bézier Variant Of Certain Summation-Integral Type Operators, Asha Ram Gairola, P. N. Agrawal Jan 2010

Direct And Inverse Theorems For The Bézier Variant Of Certain Summation-Integral Type Operators, Asha Ram Gairola, P. N. Agrawal

Turkish Journal of Mathematics

Recently, the Bézier variant of some well known operators were introduced (cf. [8]-[9]) and their rates of convergence for bounded variation functions have been investigated (cf. [2], [10]). In this paper we establish direct and inverse theorems for the Bézier variant of the operators M_n introduced in [5] in terms of Ditzian-Totik modulus of smoothness \omega_{\varphi^\lambda}(f,t) (0 \leqslant \lambda \leqslant1 ). These operators include the well known Baskakov-Durrmeyer and Szász-Durrmeyer type operators as special cases.

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Weak Hardy Space And Endpoint Estimates For Singular Integrals On Space Of Homogeneous Type, Yong Ding, Xinfeng Wu Jan 2010

Weak Hardy Space And Endpoint Estimates For Singular Integrals On Space Of Homogeneous Type, Yong Ding, Xinfeng Wu

Turkish Journal of Mathematics

We develop the theory of weak Hardy spaces H^{1,\infty} on space of homogeneous type. As some applications, we show that certain singular integral operators and fractional integral operators are bounded from H^{1,\infty} to L^{1,\infty} and L^{\frac{1}{1-\alpha},\infty}, respectively. We give also the endpoint estimates for Nagel and Stein's singular integrals studied in [10].

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On Harmonicity In Some Moufang-Klingenberg Planes, Basri̇ Çeli̇k, Ati̇lla Akpinar, Süleyman Çi̇ftçi̇ Jan 2010

On Harmonicity In Some Moufang-Klingenberg Planes, Basri̇ Çeli̇k, Ati̇lla Akpinar, Süleyman Çi̇ftçi̇

Turkish Journal of Mathematics

In this paper we study Moufang-Klingenberg planes M (A) defined over a local alternative ring A of dual numbers. We show that some collineations of M (A) preserve cross-ratio and thus establish a relation between harmonicity and harmonic position.

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Characterizations Of Slant Helices In Euclidean 3-Space, Levent Kula, Nejat Ekmekci̇, Yusuf Yayli, Kazim İlarslan Jan 2010

Characterizations Of Slant Helices In Euclidean 3-Space, Levent Kula, Nejat Ekmekci̇, Yusuf Yayli, Kazim İlarslan

Turkish Journal of Mathematics

In this paper we investigate the relations between a general helix and a slant helix. Moreover, we obtain some differential equations which they are characterizations for a space curve to be a slant helix. Also, we obtain the slant helix equations and its Frenet aparatus.

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On Purely Real Surfaces In Kaehler Surfaces, Bang-Yen Chen Jan 2010

On Purely Real Surfaces In Kaehler Surfaces, Bang-Yen Chen

Turkish Journal of Mathematics

An immersion \phi colon M to \tilde M^2 of a surface M into a Kaehler surface is called purely real if the complex structure J on \tilde M^2 carries the tangent bundle of M into a transversal bundle. In the first part of this article, we prove that the equation of Ricci is a consequence of the equations of Gauss and Codazzi for purely real surfaces in any Kaehler surface. In the second part, we obtain a necessary condition for a purely real surface in a complex space form to be minimal. Several applications of this condition are provided. In …

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On The Codifferential Of The Kähler Form And Cosymplectic Metrics On Maximal Flag Manifolds, Marlio Paredes, Sofia Pinzon Jan 2010

On The Codifferential Of The Kähler Form And Cosymplectic Metrics On Maximal Flag Manifolds, Marlio Paredes, Sofia Pinzon

Turkish Journal of Mathematics

Using moving frames we obtain a formula to calculate the codifferential of the Kähler form on a maximal flag manifold. We use this formula to obtain some differential type conditions so that a metric on the classical maximal flag manifold be cosymplectic.

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An Expansion Result For A Sturm-Liouville Eigenvalue Problem With Impulse, Şeri̇fe Faydaoğlu, Gusein Sh. Guseinov Jan 2010

An Expansion Result For A Sturm-Liouville Eigenvalue Problem With Impulse, Şeri̇fe Faydaoğlu, Gusein Sh. Guseinov

Turkish Journal of Mathematics

The paper is concerned with an eigenvalue problem for second order differential equations with impulse. Such a problem arises when the method of separation of variables applies to the heat conduction equation for two-layered composite. The existence of a countably infinite set of eigenvalues and eigenfunctions is proved and a uniformly convergent expansion formula in the eigenfunctions is established.

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Traveling Wavefronts In A Single Species Model With Nonlocal Diffusion And Age-Structure, Xue-Shi Li, Guo Lin Jan 2010

Traveling Wavefronts In A Single Species Model With Nonlocal Diffusion And Age-Structure, Xue-Shi Li, Guo Lin

Turkish Journal of Mathematics

This paper is concerned with the existence of monotone traveling wavefronts in a single species model with nonlocal diffusion and age-structure. We first apply upper and lower solution technique to prove the result if the wave speed is larger than a threshold depending only on the basic parameters. When the wave speed equals to the threshold, we show the conclusion by passing to a limit function.

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The Linear Functionals On Fundamental Locally Multiplicative Topological Algebras, E. Ansari-Piri Jan 2010

The Linear Functionals On Fundamental Locally Multiplicative Topological Algebras, E. Ansari-Piri

Turkish Journal of Mathematics

In this paper we study the dual space of fundamental locally multiplicative topological algebras and prove some results for linear and multiplicative linear functionals on these algebras. An investigation on locally compactness of the carrier space of these algebras is the last part of this note.

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Warped Product Semi-Slant Submanifolds In Kenmotsu Manifolds, Mehmet Atçeken Jan 2010

Warped Product Semi-Slant Submanifolds In Kenmotsu Manifolds, Mehmet Atçeken

Turkish Journal of Mathematics

In this paper, we research the existence or non-existence of warped product semi-slant submanifolds in Kenmotsu manifolds. Consequently, we see that there are no proper warped product semi-slant submanifolds in Kenmotsu manifolds such that totally geodesic and totally umbilical submanifolds of warped product are proper semi-slant and invariant (or anti-invariant), respectively.

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A Short Survey On Mathematical Work Of Cemal Koç, İsmai̇l Şuayi̇p Güloğlu Jan 2010

A Short Survey On Mathematical Work Of Cemal Koç, İsmai̇l Şuayi̇p Güloğlu

Turkish Journal of Mathematics

No abstract provided.

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Swan Conductors And Torsion In The Logarithmic De Rham Complex, Si̇nan Ünver Jan 2010

Swan Conductors And Torsion In The Logarithmic De Rham Complex, Si̇nan Ünver

Turkish Journal of Mathematics

We prove, for an arithmetic scheme X/S over a discrete valuation ring whose special fiber is a strict normal crossings divisor in X, that the Swan conductor of X/S is equal to the Euler characteristic of the torsion in the logarithmic de Rham complex of X/S. This is a precise logarithmic analog of a theorem by Bloch [1].

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On Abelian Rings, Nazim Agayev, Abdullah Harmanci, Sai̇t Halicioğlu Jan 2010

On Abelian Rings, Nazim Agayev, Abdullah Harmanci, Sai̇t Halicioğlu

Turkish Journal of Mathematics

Let \alpha be an endomorphism of an arbitrary ring R with identity. In this note, we introduce the notion of \alpha-abelian rings which generalizes abelian rings. We prove that \alpha-reduced rings, \alpha-symmetric rings, \alpha-semicommutative rings and \alpha-Armendariz rings are \alpha-abelian. For a right principally projective ring R, we also prove that R is \alpha-reduced if and only if R is \alpha-symmetric if and only if R is \alpha-semicommutative if and only if R is \alpha-Armendariz if and only if R is \alpha-Armendariz of power series type if and only if R is \alpha-abelian.

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Pseudo Simplicial Groups And Crossed Modules, İlker Akça, Sedat Pak Jan 2010

Pseudo Simplicial Groups And Crossed Modules, İlker Akça, Sedat Pak

Turkish Journal of Mathematics

In this paper, we define the notion of pseudo 2-crossed module and give a relation between the pseudo 2-crossed modules and pseudo simplicial groups with Moore complex of length 2.

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On Weakly M-Supplemented Primary Subgroups Of Finite Groups, Long Miao, Wolfgang Lempken Jan 2010

On Weakly M-Supplemented Primary Subgroups Of Finite Groups, Long Miao, Wolfgang Lempken

Turkish Journal of Mathematics

A subgroup H of a group G is said to be weakly M-supplemented in G if there exists a subgroup B of G provided that (1) G=HB, and (2) if H_1/H_G is a maximal subgroup of H/H_G, then H_1B=BH_1

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Statistical Convergence Of Max-Product Approximating Operators, Oktay Duman Jan 2010

Statistical Convergence Of Max-Product Approximating Operators, Oktay Duman

Turkish Journal of Mathematics

In this study, using the notion of statistical convergence, we obtain various statistical approximation theorems for a general sequence of max-product approximating operators, including Shepard type operators, although its classical limit fails. We also compute the corresponding statistical rates of the approximation.

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On Construction Of Coherent States Associated With Homogeneous Spaces, Ali Akbar Arefijamaal Jan 2010

On Construction Of Coherent States Associated With Homogeneous Spaces, Ali Akbar Arefijamaal

Turkish Journal of Mathematics

In this article, assume that G=H\times_{\tau} K is the semidirect product of two locally compact groups H and K, respectively and consider the quasi regular representation on G. Then for some closed subgroups of G we investigate an admissible condition to generate the Gilmore-Perelomov coherent states. The construction yields a wide variety of coherent states, labelled by a homogeneous space of G.

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