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Full-Text Articles in Physical Sciences and Mathematics

Invariant Subspace Problem For Positive L-Weakly And M-Weakly Compact Operators, Cevri̇ye Tonyali, Erdal Bayram Jan 2011

Invariant Subspace Problem For Positive L-Weakly And M-Weakly Compact Operators, Cevri̇ye Tonyali, Erdal Bayram

Turkish Journal of Mathematics

In this paper, we show that positive L-weakly and M-weakly compact operators on some real Banach lattices have a non-trivial closed invariant subspace. Also, we prove that any positive L-weakly (or M-weakly) compact operator T:E \rightarrow E\ has a non-trivial closed invariant subspace if there exists a Dunford-Pettis operator S:E \rightarrow E satisfying 0 \leq T \leq S, where E is Banach lattice.


Products Of Multiplication, Composition And Differentiation Between Weighted Bergman-Nevanlinna And Bloch-Type Spaces, Ajay K. Sharma Jan 2011

Products Of Multiplication, Composition And Differentiation Between Weighted Bergman-Nevanlinna And Bloch-Type Spaces, Ajay K. Sharma

Turkish Journal of Mathematics

Let \varphi and \psi be holomorphic maps on D such that \varphi ( D ) \subset D . Let C_{\varphi} , M_{\psi} and D be the composition, multiplication and differentiation operators, respectively. In this paper, we consider linear operators induced by products of these operators from Bergman-Nevanlinna spaces A^{\beta}_N to Bloch-type spaces. In fact, we prove that these operators map A^{\beta}_N compactly into Bloch-type spaces if and only if they map A^{\beta}_N boundedly into these spaces.


Domination Polynomials Of Cubic Graphs Of Order 10, Saeid Alikhani, Yee-Hock Peng Jan 2011

Domination Polynomials Of Cubic Graphs Of Order 10, Saeid Alikhani, Yee-Hock Peng

Turkish Journal of Mathematics

Let G be a simple graph of order n. The domination polynomial of G is the polynomial D(G,x)=\sum_{i=\gamma(G)}^n d(G,i) x^i, where d(G,i) is the number of dominating sets of G of size i, and \gamma(G) is the domination number of G. In this paper we study the domination polynomials of cubic graphs of order 10. As a consequence, we show that the Petersen graph is determined uniquely by its domination polynomial.


Pseudo Pq-Injective Modules, Zhanmin Zhu Jan 2011

Pseudo Pq-Injective Modules, Zhanmin Zhu

Turkish Journal of Mathematics

A module M_R is called Pseudo PQ-injective (or PPQ-injective for short) if every monomorphism from a principal submodule of M to M extends to an endomorphism of M. Some characterizations and properties of this class of modules are investigated, PPQ-injective modules with some additional conditions are studied, semisimple artinian rings are characterized by PPQ-injective modules.


Multi-Dimensional Weiss Operators, Sergey Bori̇senok, Mehmet Hakan Erkut, Yaşar Polatoğlu, Rüştü Murat Demi̇rer Jan 2011

Multi-Dimensional Weiss Operators, Sergey Bori̇senok, Mehmet Hakan Erkut, Yaşar Polatoğlu, Rüştü Murat Demi̇rer

Turkish Journal of Mathematics

We present a solution of the Weiss operator family generalized for the case of R^d and formulate a d-dimensional analogue of the Weiss Theorem. Most importantly, the generalization of the Weiss Theorem allows us to find a subset of null class functions for a partial differential equation with the generalized Weiss operators. We illustrate the significance of our approach through several examples of both linear and non-linear partial differential equations.


Graded Multiplication Modules And The Graded Ideal \Theta_G (M), Shahabaddin Ebrahimi Atani, Reza Ebrahimi Atani Jan 2011

Graded Multiplication Modules And The Graded Ideal \Theta_G (M), Shahabaddin Ebrahimi Atani, Reza Ebrahimi Atani

Turkish Journal of Mathematics

Let G be a group and let R be a G-graded commutative ring. For a graded R-module M, the notion of the associated graded ideal \theta_g (M) of R is defined. It is proved that the graded ideal \theta_g (M) is important in the study of graded multiplication modules. Among various application given, the following results are proved: if M is a graded faithful multiplication module, then \theta_g (M) is an idempotent graded multiplication ideal of R such that \theta_g (\theta_g (M)) = \theta_g (M), and every graded representable multiplication R-module is finitely generated.


Generalized Derivations On Lie Ideals In Prime Rings, Öznur Gölbaşi, Emi̇ne Koç Jan 2011

Generalized Derivations On Lie Ideals In Prime Rings, Öznur Gölbaşi, Emi̇ne Koç

Turkish Journal of Mathematics

Let R be a prime ring with characteristic different from two, U a nonzero Lie ideal of R and f be a generalized derivation associated with d. We prove the following results: (i) If [u,f(u)] \in Z, for all u \in U, then U \subset Z. (ii) (f,d) and (g,h) be two generalized derivations of R such that f(u)v=ug(v), for all u,v \in U, then U \subset Z. (iii) f([u,v])=\pm \lbrack u,v], for all u,v\in U, then U \subset Z.


On The Stability Of Basisness In L_P(1 < P < +\Infty) Of Cosines And Sines, Ali Huseynli Jan 2011

On The Stability Of Basisness In L_P(1 < P < +\Infty) Of Cosines And Sines, Ali Huseynli

Turkish Journal of Mathematics

We study the basis properties in L_p(0, \pi) (1 < p < \infty) of the solution system of Sturm--Liouville equations with different types of initial conditions. We first establish some results on the stability of the basis property of cosines and sines in L_p(0, \pi) (1 < p < \infty) and then show that the solution system above forms a basis in L_p(0, \pi) if and only if certain cosine system (or sine system, depending on type of initial conditions) forms a basis in L_p(0, \pi).


Order Continuous Operators On Cd_0(K,E) And Cd_W(K,E)-Spaces, Faruk Polat Jan 2011

Order Continuous Operators On Cd_0(K,E) And Cd_W(K,E)-Spaces, Faruk Polat

Turkish Journal of Mathematics

In [2], Alpay and Ercan characterized order continuous duals of spaces CD_0(K, E) and CD_w(K, E) where K is a compact Hausdorff space without isolated points and E is a Banach lattice. In this note, we generalize their results to an arbitrary Dedekind complete Banach lattice F, that is to say, we characterize order continuous operators on these spaces taking values in an arbitrary Dedekind complete Banach lattice F.


Slant Lightlike Submanifolds Of Indefinite Kenmotsu Manifolds, Ram Gupta, Sharfuddin Ahamad Jan 2011

Slant Lightlike Submanifolds Of Indefinite Kenmotsu Manifolds, Ram Gupta, Sharfuddin Ahamad

Turkish Journal of Mathematics

In this paper, we introduce the notion of a slant lightlike submanifold of an indefinite Kenmotsu manifold. We provide a non-trivial example and obtain necessary and sufficient conditions for the existence of a slant lightlike submanifold. Also, we give an example of a minimal slant lightlike submanifold of R_2^{9} and prove some characterization theorems.


Relative Nullity Foliations And Lightlike Hypersurfaces In Indefinite Kenmotsu Manifolds, Fortune Massamba Jan 2011

Relative Nullity Foliations And Lightlike Hypersurfaces In Indefinite Kenmotsu Manifolds, Fortune Massamba

Turkish Journal of Mathematics

This paper deals with the relative nullity distributions of lightlike hypersurfaces of indefinite Kenmotsu space forms, tangent to the structure vector field. Theorems on parallel vector fields are obtained. We give characterization theorems for the relative nullity distributions as well as for Einstein, totally contact umbilical and flat lightlike hypersurfaces. We show that, under a certain condition, Einstein lightlike hypersurfaces in indefinite Kenmotsu space forms have parallel screen distributions. We prove that on a parallel (or totally umbilical) lightlike hypersurface, the relative nullity space coincides with the tangent vector space.


Jackknife And Bootstrap With Cycling Blocks For The Estimation Of Fractional Parameter In Arfima Model, Lorenc Ekonomi, Argjir Butka Jan 2011

Jackknife And Bootstrap With Cycling Blocks For The Estimation Of Fractional Parameter In Arfima Model, Lorenc Ekonomi, Argjir Butka

Turkish Journal of Mathematics

One of most important problems concerning the ARFIMA time series model is the estimation of fractional parameter d. Various methods have been used to solve this problem, such as the log-periodogram regression of a process. In this article we propose two jackknife and bootstrap methods, which aid in the estimation of fractional parameter d. These methods involve non-overlapping blocks and moving blocks with random starting point and length. We have conducted several simulations and the results show that the estimations obtained are very close to the real parameter value.


On Generalized Witt Algebras In One Variable, Ki Bong Nam, Jonathan Pakianathan Jan 2011

On Generalized Witt Algebras In One Variable, Ki Bong Nam, Jonathan Pakianathan

Turkish Journal of Mathematics

We study a class of infinite dimensional Lie algebras called generalized Witt algebras (in one variable). These include the classical Witt algebra and the centerless Virasoro algebra as important examples. We show that any such generalized Witt algebra is a semisimple, indecomposable Lie algebra which does not contain any abelian Lie subalgebras of dimension greater than one. We develop an invariant of these generalized Witt algebras called the spectrum, and use it to show that there exist infinite families of nonisomorphic, simple, generalized Witt algebras and infinite families of nonisomorphic, nonsimple, generalized Witt algebras. We develop a machinery that can …


B. Y. Chen Inequalities For Submanifolds Of A Riemannian Manifold Of Quasi-Constant Curvature, Ci̇han Özgür Jan 2011

B. Y. Chen Inequalities For Submanifolds Of A Riemannian Manifold Of Quasi-Constant Curvature, Ci̇han Özgür

Turkish Journal of Mathematics

In this paper, we prove B. Y. Chen inequalities for submanifolds of a Riemannian manifold of quasi-constant curvature, i.e., relations between the mean curvature, scalar and sectional curvatures, Ricci curvatures and the sectional curvature of the ambient space. The equality cases are considered.


Analysis Of A Differential Equation Model Of Hiv Infection Of Cd4^+ T-Cells With Saturated Reverse Function, Xiangyun Shi, Gang Li, Xueyong Zhou, Xinyu Song Jan 2011

Analysis Of A Differential Equation Model Of Hiv Infection Of Cd4^+ T-Cells With Saturated Reverse Function, Xiangyun Shi, Gang Li, Xueyong Zhou, Xinyu Song

Turkish Journal of Mathematics

In this paper, an ordinary differential equation model of HIV infection of CD4^+ T-cells with saturated reverse function is studied. We prove that if the basic reproduction number R_0


Null Mannheim Curves In The Minkowski 3-Space E_1^3, Handan Özteki̇n, Mahmut Ergüt Jan 2011

Null Mannheim Curves In The Minkowski 3-Space E_1^3, Handan Özteki̇n, Mahmut Ergüt

Turkish Journal of Mathematics

In this study, we give the definition of null Mannheim curve with timelike or spacelike Mannheim partner curve in the Minkowski 3-space E _1^3. We get the necessary and sufficient conditions for the null Mannheim curves. Then we investigate the null and timelike or spacelike generalized helix as the null Mannheim curve and timelike or spacelike Mannheim partner curve, respectively.


Central Simple Superalgebras With Superantiautomorphism Of Order Two Of The Second Kind, Ameer Jaber Jan 2011

Central Simple Superalgebras With Superantiautomorphism Of Order Two Of The Second Kind, Ameer Jaber

Turkish Journal of Mathematics

Our main purpose is to develop the theory of existence of superantiautomorphisms of order two of the second kind (which are caled superinvolutions of the second kind) on finite dimensional central simple superalgebras A=M_n(D), where D is a finite dimensional division superalgebra with nontrivial grading over K, where K is a field of any characteristic. We determine which finite dimensional central simple superalgebras posses a superinvolution of the second kind and put these results in the context of the Albert-Reihm Theorem on the existence of involutions of the second kind.


A Boundary Value Problem For Bitsadze Equation In Matrix Form, Sezayi̇ Hizliyel, Mehmet Çağliyan Jan 2011

A Boundary Value Problem For Bitsadze Equation In Matrix Form, Sezayi̇ Hizliyel, Mehmet Çağliyan

Turkish Journal of Mathematics

In this work, we investigate the solvability of the problem \frac{\partial^2w}{\partial \overline\phi ^2}=f Re\{i\phi(z)w(z)\}=\gamma_1(z),Rew_{\overline\phi}(z)=\gamma_2(z) z \in \partial D in the unit disk of complex plane. Here f , \gamma_1 and \gamma_2 are given m \times s-complex matrix-valued functions; f\in L^{p} (\overline{D}), \gamma_1, \gamma_2 \in C(\partial D) and \phi is a generating solution for Q-holomorphic functions.


Existence Of Three Solutions To A Non-Homogeneous Multi-Point Bvp Of Second Order Differential Equations, Yuji Liu Jan 2011

Existence Of Three Solutions To A Non-Homogeneous Multi-Point Bvp Of Second Order Differential Equations, Yuji Liu

Turkish Journal of Mathematics

This paper is concerned with a non-homogeneous multi-point boundary value problem of second order differential equation with one-dimensional p-Laplacian. Using multiple fixed point theorems, sufficient conditions to guarantee the existence of at least three solutions of this kind of BVP are established. Two examples are presented to illustrate the main results.


Nilpotent Elements And Reduced Rings, Junchao Wei, Libin Li Jan 2011

Nilpotent Elements And Reduced Rings, Junchao Wei, Libin Li

Turkish Journal of Mathematics

In this paper, we show the following results: (1) R is a min-leftsemicentral ring if and only if eR(1-e)Re=0 for all e \in ME_l(R); (2) Quasi-normal rings, NI rings and weakly reversible rings are all min-leftsemicentral ring; (3) R is left MC2 ring if and only if aRe=0 implies eRa=0 for all e \in ME_l(R) and a \in R if and only if every projective simple left R-module is MUP-injective; (4) R is reduced if and only if R is n-regular and quasi-normal if and only if R is n-regular and weakly reversible; (5) R is strongly regular if and …


Blow-Up Time For A Semilinear Parabolic Equation With Variable Reaction, Theodore Kouassi Boni, Remi Kouadio Kouakou Jan 2011

Blow-Up Time For A Semilinear Parabolic Equation With Variable Reaction, Theodore Kouassi Boni, Remi Kouadio Kouakou

Turkish Journal of Mathematics

In this paper, we address the solution of a semilinear heat equation with variable reaction subject to Dirichlet boundary conditions and nonnegative initial datum. Under some assumptions, we show that the solution of the above problem blows up in a finite time, and its blow-up time goes to that of the solution of a certain differential equation. Finally, we give some numerical results to illustrate our analysis.


Homology With Respect To A Kernel Transformation, Seyed Naser Hosseini, Mohammad Zaher Kazemi Baneh Jan 2011

Homology With Respect To A Kernel Transformation, Seyed Naser Hosseini, Mohammad Zaher Kazemi Baneh

Turkish Journal of Mathematics

In this article we first give the relations between commonly used images of a morphism in a category. We then investigate d-homology in a category with certain properties, for a kernel transformation d. In particular, we show that, in an abelian category, d-homology, where d is induced by the subtraction operation, is the standard homology and that in more general categories the d-homology for a trivial d is zero. We also compute through examples the d-homology for certain kernel transformations d in such categories as R-modules, abelian groups and short exact sequences of R-modules. Finally, we characterize kernel transformations in …


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.


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].


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.


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.


The Essential Norm Of A Composition Operator On Orlicz Spaces, M. R. Jabbarzadeh Jan 2010

The Essential Norm Of A Composition Operator On Orlicz Spaces, M. R. Jabbarzadeh

Turkish Journal of Mathematics

In this note we determine the lower and upper estimates for the essential norm of a composition operator on the Orlicz spaces under certain conditions.


Number Of Pseudo--Anosov Elements In The Mapping Class Group Of A Four--Holed Sphere, Feri̇he Atalan, Mustafa Korkmaz Jan 2010

Number Of Pseudo--Anosov Elements In The Mapping Class Group Of A Four--Holed Sphere, Feri̇he Atalan, Mustafa Korkmaz

Turkish Journal of Mathematics

We compute the growth series and the growth functions of reducible and pseudo-Anosov elements of the pure mapping class group of the sphere with four holes with respect to a certain generating set. We prove that the ratio of the number of pseudo-Anosov elements to that of all elements in a ball with center at the identity tends to one as the radius of the ball tends to infinity.


Some Properties Of C-Fusion Frames, Mohammad Hasan Faroughi, Reza Ahmadi Jan 2010

Some Properties Of C-Fusion Frames, Mohammad Hasan Faroughi, Reza Ahmadi

Turkish Journal of Mathematics

In [10], we generalized the concept of fusion frames, namely, c-fusion frames, which is a continuous version of the fusion frames. In this article we give some important properties about the generalization, namely erasures of subspaces, the bound of c-erasure reconstruction error for Parseval c-fusion frames, perturbation of c-fusion frames and the frame operator for fusion pair.


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.