Open Access. Powered by Scholars. Published by Universities.®

Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Articles 2011 - 2040 of 2595

Full-Text Articles in Mathematics

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.


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.


Generalized Catalan Numbers, Sequences And Polynomials, Cemal Koç, İsmai̇l Güloğlu, Songül Esi̇n Jan 2010

Generalized Catalan Numbers, Sequences And Polynomials, Cemal Koç, İsmai̇l Güloğlu, Songül Esi̇n

Turkish Journal of Mathematics

In this paper we present an algebraic interpretation for generalized Catalan numbers. We describe them as dimensions of certain subspaces of multilinear polynomials. This description is of utmost importance in the investigation of annihilators in exterior algebras.


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].


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.


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.


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.


Order-Isomorphism And A Projection's Diagram Of C(X), Ahmed S. Al-Rawashdeh, Sultan M. Al-Suleiman Jan 2010

Order-Isomorphism And A Projection's Diagram Of C(X), Ahmed S. Al-Rawashdeh, Sultan M. Al-Suleiman

Turkish Journal of Mathematics

A mapping between projections of C^*-algebras preserving the orthogonality, is called an orthoisomorphism. We define the order-isomorphism mapping on C^*-algebras, and using Dye's result, we prove in the case of commutative unital C^*-algebras that the concepts; order-isomorphism and the orthoisomorphism coincide. Also, we define the equipotence relation on the projections of C(X); indeed, new concepts of finiteness are introduced. The classes of projections are represented by constructing a special diagram, we study the relation between the diagram and the topological space X. We prove that an order-isomorphism, which preserves the equipotence of projections, induces a diagram-isomorphism; also if two diagrams …


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.


Complete Systems Of Differential Invariants Of Vector Fields In A Euclidean Space, Djavvat Khadjiev Jan 2010

Complete Systems Of Differential Invariants Of Vector Fields In A Euclidean Space, Djavvat Khadjiev

Turkish Journal of Mathematics

The system of generators of the differential field of all G-invariant differential rational functions of a vector field in the n-dimensional Euclidean space R^n is described for groups G=M(n) and G=SM(n), where M(n) is the group of all isometries of R^n and SM(n) is the group of all euclidean motions of R^n. Using these results, vector field analogues of the first part of the Bonnet theorem for groups Aff(n), M(n), SM(n) in R^n are obtained, where Aff(n) is the group of all affine transformations of R^n. These analogues are given in terms of the first fundamental form and Christoffel symbols …


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.


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.


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.


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


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.


Transversal Lightlike Submanifolds Of Indefinite Sasakian Manifolds, Cumali̇ Yildirim, Bayram Şahi̇n Jan 2010

Transversal Lightlike Submanifolds Of Indefinite Sasakian Manifolds, Cumali̇ Yildirim, Bayram Şahi̇n

Turkish Journal of Mathematics

We study both radical transversal and transversal lightlike submanifolds of indefinite Sasakian manifolds. We give examples, investigate the geometry of distributions and obtain necessary and sufficient conditions for the induced connection on these submanifolds to be metric connection. We also study totally contact umbilical radical transversal and transversal lightlike submanifolds of indefinite Sasakian manifolds and obtain a classification theorem for totally contact umbilical transversal lightlike submanifolds.


Chaos In Product Maps, Nedi̇m Deği̇rmenci̇, Şahi̇n Koçak Jan 2010

Chaos In Product Maps, Nedi̇m Deği̇rmenci̇, Şahi̇n Koçak

Turkish Journal of Mathematics

We discuss how chaos conditions on maps carry over to their products. First we give a counterexample showing that the pro\-duct of two chaotic maps (in the sense of Devaney) need not be chaotic. We then remark that if two maps (or even one of them) exhibit sensitive dependence on initial conditions, so does their product; likewise, if two maps possess dense periodic points, so does their product. On the other side, the product of two topologically transitive maps need not be topologically transitive. We then give sufficient conditions under which the product of two chaotic maps is chaotic in …


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.


Finite Subquandles Of Sphere, Nüli̇fer Özdemi̇r, Hüseyi̇n Azcan Jan 2010

Finite Subquandles Of Sphere, Nüli̇fer Özdemi̇r, Hüseyi̇n Azcan

Turkish Journal of Mathematics

In this work finite subquandles of sphere are classified by using classification of subgroups of orthogonal group O(3). For any subquandle Q of sphere there is a subgroup G_Q of O(3) associated with Q. It is shown that if Q is a finite (infinite) subquandle, then G_Q is a finite (infinite) subgroup. Finite subquandles of sphere are obtained from actions of finite subgroups of SO(3) on sphere. It is proved that the finite subquandles Q_1 and Q_2 of sphere whose all elements are not on the same great circle are isomorphic if and only if the subgroups G_{Q_1} and G_{Q_2} …


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.


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.


Notes On Null Curves In Minkowski Spaces, Makoto Sakaki Jan 2010

Notes On Null Curves In Minkowski Spaces, Makoto Sakaki

Turkish Journal of Mathematics

We show a correspondence between the evolute of a null curve and the involute of a certain spacelike curve in the 4-dimensional Minkowski space. Also we characterize pseudo-spherical null curves in the n-dimensional Minkowski space in terms of the curvature functions.


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.


Stack-Sortable Permutations And Polynomials, İsmai̇l Ş. Güloğlu, Cemal Koç Jan 2009

Stack-Sortable Permutations And Polynomials, İsmai̇l Ş. Güloğlu, Cemal Koç

Turkish Journal of Mathematics

The Catalan numbers show up in a diverse variety of counting problems. In this note we give yet another characterization of the Catalan number C(n). It is characterized as the dimension of a certain space of multilinear polynomials by exhibiting a basis.


Values Of The Carmichael Function Equal To A Sum Of Two Squares, William D. Banks, Ahmet M. Güloğlu Jan 2009

Values Of The Carmichael Function Equal To A Sum Of Two Squares, William D. Banks, Ahmet M. Güloğlu

Turkish Journal of Mathematics

In this note, we determine the order of growth of the number of positive integers n \le x such that \lambda(n) is a sum of two square numbers, where \lambda(n) is the Carmichael function.


Lebesgue-Stieltjes Measure On Time Scales, Asli Deni̇z, Ünal Ufuktepe Jan 2009

Lebesgue-Stieltjes Measure On Time Scales, Asli Deni̇z, Ünal Ufuktepe

Turkish Journal of Mathematics

The theory of time scales was introduced by Stefan Hilger in his Ph. D. thesis in 1988, supervised by Bernd Auldbach, in order to unify continuous and discrete analysis [5]. Measure theory on time scales was first constructed by Guseinov [4], then further studies were made by Guseinov-Bohner [1], Cabada-Vivero [2] and Rzezuchowski [6]. In this article, we adapt the concept of Lebesgue-Stieltjes measure to time scales. We define Lebesgue-Stieltjes \Delta and \nabla-measures and by using these measures, we define an integral adapted to time scales, specifically Lebesgue-Stieltjes \Delta-integral. We also establish the relation between Lebesgue-Stieltjes measure and Lebesgue-Stieltjes \Delta-measure, …


Korovkin Type Error Estimates For Positive Linear Operators Involving Some Special Functions, Ogün Doğru, Esra Erkuş-Duman Jan 2009

Korovkin Type Error Estimates For Positive Linear Operators Involving Some Special Functions, Ogün Doğru, Esra Erkuş-Duman

Turkish Journal of Mathematics

In the present paper, we introduce a new sequence of linear positive operators with the help of generating functions. We obtain some Korovkin type approximation properties for these operators and compute rates of convergence by means of the first and second order modulus of continuities and Peetre´s K-functional. In order to obtain explicit expressions for the first and second moment of our operators, we obtain a functional differential equation including our operators. Furthermore, we deal with a modification of our operators converging to integral of function f on the interval (0,1).


Multiple Positive Solutions For Nonlinear Third-Order Boundary Value Problems In Banach Spaces, Feng Wang, Hai-Hua Lu, Fang Zhang Jan 2009

Multiple Positive Solutions For Nonlinear Third-Order Boundary Value Problems In Banach Spaces, Feng Wang, Hai-Hua Lu, Fang Zhang

Turkish Journal of Mathematics

This paper deals with the positive solutions of nonlinear boundary value problems in Banach spaces. By using fixed point index theory, some sufficient conditions for the existence of at least one or two positive solutions to boundary value problems in Banach spaces are obtained. An example illustrating the main results is given.


Cartan Calculus On The Quantum Space R_Q^3, Sali̇h Çeli̇k, E. Mehmet Özkan, Ergün Yaşar Jan 2009

Cartan Calculus On The Quantum Space R_Q^3, Sali̇h Çeli̇k, E. Mehmet Özkan, Ergün Yaşar

Turkish Journal of Mathematics

To give a Cartan calculus on the extended quantum 3d space, the noncommutative differential calculus on the extended quantum 3d space is extended by introducing inner derivations and Lie derivatives.


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 …