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Full-Text Articles in Physical Sciences and Mathematics

On Modules Which Satisfy The Radical Formula, Bülent Saraç, Yücel Tiraş Jan 2013

On Modules Which Satisfy The Radical Formula, Bülent Saraç, Yücel Tiraş

Turkish Journal of Mathematics

In this paper, the authors prove that every representable module over a commutative ring with identity satisfies the radical formula. With this result, they extend the class of modules satisfying the radical formula from that of Artinian modules to a larger one. They conclude their work by giving a description of the radical of a submodule of a representable module.


Generalized Sobolev-Shubin Spaces, Boundedness And Schatten Class Properties Of Toeplitz Operators, Ayşe Sandikçi, Ahmet Turan Gürkanli Jan 2013

Generalized Sobolev-Shubin Spaces, Boundedness And Schatten Class Properties Of Toeplitz Operators, Ayşe Sandikçi, Ahmet Turan Gürkanli

Turkish Journal of Mathematics

Let w and \omega be two weight functions on R^{2d} and 1 \leq p,q \leq \infty. Also let M(p,q,\omega) (R^d) denote the subspace of tempered distributions S' (R^d) consisting of f \in S' (R^d) such that the Gabor transform V_g f of f is in the weighted Lorentz space L(p,q,\omega d\mu) (R^{2d}) . In the present paper we define a space Q_{g,w}^{M(p,q,\omega) (R^d) as counter image of M(p,q,\omega) (R^d) under Toeplitz operator with symbol w. We show that Q_{g,w}^{M(p,q,\omega)}(R^d) is a generalization of usual Sobolev-Shubin space Q_s (R^d). We also investigate the boundedness and Schatten-class properties of Toeplitz operators.


On The Nilpotent Graph Of A Ring, Mohammad Javad Nikmehr, Soheila Khojasteh Jan 2013

On The Nilpotent Graph Of A Ring, Mohammad Javad Nikmehr, Soheila Khojasteh

Turkish Journal of Mathematics

Let R be a ring with unity. The nilpotent graph of R, denoted by \Gamma_N(R), is a graph with vertex set Z_N(R)^* = {0 \neq x \in R \mid xy \in N(R) for some 0 \neq y \in R}; and two distinct vertices x and y are adjacent if and only if xy \in N(R), where N(R) is the set of all nilpotent elements of R. Recently, it has been proved that if R is a left Artinian ring, then diam(\Gamma_N(R)) \leq 3. In this paper, we present a new proof for the above result, where R is a finite …


On Some Results On Ip-Graphs, Roghayeh Hafezieh, Moohammadali Iranmanesh Jan 2013

On Some Results On Ip-Graphs, Roghayeh Hafezieh, Moohammadali Iranmanesh

Turkish Journal of Mathematics

The IP-graph of a naturally valenced association scheme and some of its properties have been studied recently. In this paper we introduce the bipartite version of this graph for a naturally valenced association scheme (X,S), denoted by BIP(S). We also investigate some of its properties.


On The Centroid Of Prime Semirings, Hasret Yazarli, Mehmet Ali̇ Öztürk Jan 2013

On The Centroid Of Prime Semirings, Hasret Yazarli, Mehmet Ali̇ Öztürk

Turkish Journal of Mathematics

We define and study the extended centroid of a prime semiring. We show that the extended centroid is a semifield and give some properties of the centroid of a right multiplicatively cancellable prime semiring.


Finitistic Dimension Conjectures For Representations Of Quivers, Sergio Estrada, Salahatti̇n Özdemi̇r Jan 2013

Finitistic Dimension Conjectures For Representations Of Quivers, Sergio Estrada, Salahatti̇n Özdemi̇r

Turkish Journal of Mathematics

Let R be a ring and Q be a quiver. We prove the first Finitistic Dimension Conjecture to be true for RQ, the path ring of Q over R, provided that R satisfies the conjecture. In fact, we prove that if the little and the big finitistic dimensions of R coincide and equal n


Products Of Conjugacy Classes And Products Of Irreducible Characters In Finite Groups, Mohammad Reza Darafsheh, Sajjad Mahmood Robati Jan 2013

Products Of Conjugacy Classes And Products Of Irreducible Characters In Finite Groups, Mohammad Reza Darafsheh, Sajjad Mahmood Robati

Turkish Journal of Mathematics

Let G be a finite group. If A and B are two conjugacy classes in G, then AB is a union of conjugacy classes in G and \eta(AB) denotes the number of distinct conjugacy classes of G contained in AB. If \chi and \psi are two complex irreducible characters of G, then \chi\psi is a character of G and again we let \eta(\chi\psi) be the number of irreducible characters of G appearing as constituents of \chi\psi. In this paper our aim is to study the product of conjugacy classes in a finite group and obtain an upper bound for \eta …


Global Existence, Decay And Blow Up Solutions For Coupled Nonlinear Wave Equations With Damping And Source Terms, Erhan Pi̇şki̇n, Necat Polat Jan 2013

Global Existence, Decay And Blow Up Solutions For Coupled Nonlinear Wave Equations With Damping And Source Terms, Erhan Pi̇şki̇n, Necat Polat

Turkish Journal of Mathematics

We study the initial-boundary value problem for a system of nonlinear wave equations with nonlinear damping and source terms, in a bounded domain. The decay estimates of the energy function are established by using Nakao's inequality. The nonexistence of global solutions is discussed under some conditions on the given parameters.


Bbm Equation With Non-Constant Coefficients, Amutha Senthilkumar Jan 2013

Bbm Equation With Non-Constant Coefficients, Amutha Senthilkumar

Turkish Journal of Mathematics

In this article, a model for the propagation of long waves over an uneven bottom is considered. We provide both theoretical and numerical results for this model. We also discuss the changes which occur in a solitary wave solution of the BBM equation as it travels through a channel of decreasing depth.


Second Order Approximations In Sequential Point Estimation Of The Probability Of Zero In Poisson Distribution, Eisa Mahmoudi, Mohammad Hatami Kamin Jan 2013

Second Order Approximations In Sequential Point Estimation Of The Probability Of Zero In Poisson Distribution, Eisa Mahmoudi, Mohammad Hatami Kamin

Turkish Journal of Mathematics

In the analysis of the count data, the Poisson model becomes overtly restrictive in the case of over-dispersed or under-dispersed data. When count data are under-dispersed, specific models such as generalized linear models (GLM) are proposed. Other examples are the zero-inflated Poisson model (ZIP) and zero-truncated Poisson model (ZTP), which have been used in literature to deal with an excess or absence of zeros in count data. Thus having a knowledge of the probability of zeros and its estimation in Poisson distribution can be significant and useful. Some estimation problems with unknown parameter cannot attain minimum risk where the sample …


Generalized Derivations Of Prime Rings On Multilinear Polynomials With Annihilator Conditions, Nurcan Argaç, Çağri Demi̇r Jan 2013

Generalized Derivations Of Prime Rings On Multilinear Polynomials With Annihilator Conditions, Nurcan Argaç, Çağri Demi̇r

Turkish Journal of Mathematics

Let K be a commutative ring with unity, R be a prime K-algebra with characteristic not 2, U be the right Utumi quotient ring of R, C the extended centroid of R, I a nonzero right ideal of R and a a fixed element of R. Let g be a generalized derivation of R and f(X_1,..., X_n) a multilinear polynomial over K. If ag(f(x_1,...,x_n))f(x_1,...,x_n)=0 for all x_1,...,x_n \in I, then one of the following holds: (1) aI=ag(I)=0; (2) g(x)=bx+[c,x] for all x\in R, where b,c\in U. In this case either [c,I]I=0=abI or aI=0=a(b+c)I; (3) [f(X_1,...,X_n),X_{n+1}]X_{n+2} is an identity for I.


Strongly Gorenstein Flat And Gorenstein Fp-Injective Modules, Chunhua Yang Jan 2013

Strongly Gorenstein Flat And Gorenstein Fp-Injective Modules, Chunhua Yang

Turkish Journal of Mathematics

In this paper, we first study the properties of strongly Gorenstein flat (resp. Gorenstein FP-injective) modules which are special Gorenstein projective (resp. Gorenstein injective) modules, and use them to prove that the global strongly Gorenstein flat dimension and the global Gorenstein FP-injective dimension of a ring R are identical when R is n-FC or commutative coherent. Finally, we show that if R is a commutative Noetherian ring, then, for any R-module M, SGfd_RM=Gpd_RM, and hence SGfd_RM< \infty if and only if Gfd_RM


Some Properties On The Baer-Invariant Of A Pair Of Groups And V_G-Marginal Series, Mohammad Reza Rismanchian, Mehdi Araskhan Jan 2013

Some Properties On The Baer-Invariant Of A Pair Of Groups And V_G-Marginal Series, Mohammad Reza Rismanchian, Mehdi Araskhan

Turkish Journal of Mathematics

The aim of this paper is to present some properties of the Baer-invariant of a pair of groups with respect to a given variety of groups V. We derive some equalities and inequalities of the Baer-invariant of a pair of finite groups, as long as V is considered to be a Schur-Baer variety. Moreover, we present a relative version of the concept of lower marginal series and give some isomorphisms among V_G-marginal factor groups. Also, we conclude a generalized version of the Stallings' theorem.


(P,\\Lambda)-Koszul Algebras And Modules, Ii, Jiafeng Lu Jan 2013

(P,\\Lambda)-Koszul Algebras And Modules, Ii, Jiafeng Lu

Turkish Journal of Mathematics

This paper is a continuous work of [14], where the notions of (p,\lambda)-Koszul algebra and (p,\lambda)-Koszul module were first introduced. More precisely, some new criteria for a positively graded algebra to be (p,\lambda)-Koszul are provided. We also generalize (p,\lambda)-Koszul objects to the nongraded case and define the so-called quasi-(p,\lambda)-Koszul objects. Further, the relationships between (quasi-) (p,\lambda)-Koszul modules and minimal Horseshoe Lemma are established.


On Nash\'S 4-Sphere And Property 2r, Motoo Tange Jan 2013

On Nash\'S 4-Sphere And Property 2r, Motoo Tange

Turkish Journal of Mathematics

D. Nash defined a family of homotopy 4-spheres in [11]. Proving that his manifolds S_{m,n,m',n'} are all real S^4, we show that they have handle decomposition with no 1-handles, two 2-handles and two 3-handles. The handle structures give new potential counterexamples to the Property 2R conjecture.


Formulas For The Fourier Coefficients Of Cusp Form For Some Quadratic Forms (Correction To A Paper By Ahmet Tekcan With The Same Title), Bariş Kendi̇rli̇ Jan 2013

Formulas For The Fourier Coefficients Of Cusp Form For Some Quadratic Forms (Correction To A Paper By Ahmet Tekcan With The Same Title), Bariş Kendi̇rli̇

Turkish Journal of Mathematics

In this study M_1(\Gamma _0(3) ,\chi _{-3}) , M_2(\Gamma_0(5), \chi _5) and M_3(\Gamma _0(7),\chi _{-7}) have been examined and the formulas for the Fourier Coefficients of theta series and the representation number of positive integers by some quadratic forms 3x_1^2+3x_1x_2+x_2^2, 5(x_1^2+x_1x_2+x_1x_3+x_1x_4+x_2^2+x_2x_3+ x_2x_4+x_3^2+x_3x_4)+2x_4^2, and 7(x_1^2+x_1x_2+x_1x_3+x_1x_4+x_1x_5+x_2^2+x_2x_3+x_2x_4+x_2x_5+ x_3^2+x_3x_4+x_3x_5+x_4^2+x_4x_5+x_5^2+7(x_1x_6+x_2x_6+x_3x_6+ x_4x_6+x_5x_6)+3x_6^2, are determined. This work is a correction to a paper of the same title by Ahmet Tekcan [5].


The Cyclic Behavior Of The Constrictive Markov Operators, César Emilio Villarreal Rodríguez Jan 2013

The Cyclic Behavior Of The Constrictive Markov Operators, César Emilio Villarreal Rodríguez

Turkish Journal of Mathematics

Let S be a Polish space, and let M_{\varSigma} be the Banach space of finite signed measures on the Borel \Sigma-algebra \varSigma of S. Given a constrictive Markov operator T:M_{\varSigma}\rightarrow M_{\varSigma}, we use the asymptotic periodic decomposition of T to determine the set of T-invariant distributions in M_{\varSigma} and the set of T-ergodic distributions. We also give the relationship between the asymptotic periodic decomposition and the cycles of the process relative to the operator T.


Continuous Invariant Averagings, Djavvat Khadjiev, Abdullah Çavuş Jan 2013

Continuous Invariant Averagings, Djavvat Khadjiev, Abdullah Çavuş

Turkish Journal of Mathematics

Main results: For every equicontinuous almost periodic linear representation of a group in a complete locally convex space L with the countability property, there exists the unique invariant averaging; it is continuous and is expressed by using the L-valued invariant mean of Bochner and von-Neumann. An analog of Wiener's approximation theorem for an equicontinuous almost periodic linear representation in a locally convex space with the countability property is proved.


An Exhaustive Computer Search For Finding New Curves With Many Points Among Fibre Products Of Two Kummer Covers Over F_5 And F_7, Ferruh Özbudak, Burcu Gülmez Temür, Oğuz Yayla Jan 2013

An Exhaustive Computer Search For Finding New Curves With Many Points Among Fibre Products Of Two Kummer Covers Over F_5 And F_7, Ferruh Özbudak, Burcu Gülmez Temür, Oğuz Yayla

Turkish Journal of Mathematics

In this paper we make an exhaustive computer search for finding new curves with many points among fibre products of 2 Kummer covers of the projective line over F_5 and F_7. At the end of the search, we have 12 records and 6 new entries for the current Table of Curves with Many Points. In particular, we observe that the fibre product y_1^3 = \frac{5(x + 2)(x + 5)}{x}, y_2^3 = \frac{3x^2(x + 5)}{x + 3} over F_7 has genus 7 with 36 rational points. As this coincides with the Ihara bound, we conclude that the maximum number N_7(7) of …


Complex Symplectic Geometry With Applications To Vector Differential Operators, Chuan Fu Yang Jan 2013

Complex Symplectic Geometry With Applications To Vector Differential Operators, Chuan Fu Yang

Turkish Journal of Mathematics

Let l(y) be a formally self-adjoint vector-valued differential expression of order n on an interval (a, \infty)(-\infty \leq a < \infty) with complex matrix-valued function coefficients and finite equal deficiency indices. In this paper, applying complex symplectic algebra, we give a reformulation for self-adjoint domains of the minimal operator associated with l(y) and classify them.


On Quotients Of Ith Affine Surface Areas, Chang-Jian Zhao Jan 2013

On Quotients Of Ith Affine Surface Areas, Chang-Jian Zhao

Turkish Journal of Mathematics

Following the volume difference function, we first introduce the notion of the affine surface area quotient function. We establish Brunn--Minkowski type inequalities for the affine surface area quotient function, which in special cases yield some well-known results.


Semi-Slant And Bi-Slant Submanifolds Of Almost Contact Metric 3-Structure Manifolds, Fereshteh Malek, Mohammad Bagher Kazemi Balgeshir Jan 2013

Semi-Slant And Bi-Slant Submanifolds Of Almost Contact Metric 3-Structure Manifolds, Fereshteh Malek, Mohammad Bagher Kazemi Balgeshir

Turkish Journal of Mathematics

In this paper we introduce the notions of semi-slant and bi-slant submanifolds of an almost contact 3-structure manifold. We give some examples and characterization theorems about these submanifolds. Moreover, the distributions of semi-slant submanifolds of 3-cosymplectic and 3-Sasakian manifolds are studied.


Foliations And A Class Of Metrics On Tangent Bundle, Esmaeil Peyghan, Leila Nourmohammadi Far Jan 2013

Foliations And A Class Of Metrics On Tangent Bundle, Esmaeil Peyghan, Leila Nourmohammadi Far

Turkish Journal of Mathematics

Let M be a smooth manifold with Finsler metric F, and let TM° be the slit tangent bundle of M with a generalized Riemannian metric G, which is induced by F. In this paper, we extract many natural foliations of (TM°,G) and study some of their geometric properties. Next we use this approach to obtain new characterizations of Finsler manifolds with positive constant curvature.


On Pseudo Semi-Projective Modules, Truong Cong Quynh Jan 2013

On Pseudo Semi-Projective Modules, Truong Cong Quynh

Turkish Journal of Mathematics

A right R-module M is called semi-projective if, for any submodule N of M, every epimorphism \pi: M \rightarrow N and every homomorphism \alpha: M \rightarrow N, there exists a homomorphism \beta: M \rightarrow M such that \pi \beta = \alpha (see [11]). In this paper, we consider some generalizations of semi-projective module, that is quasi pseudo principally projective module. Some properties of this class of module are studied.


Approximation By Iterates Of Beta Operators, Purshottam Narain Agrawal, Karunesh Kumar Singh, Vikas Kumar Mishra Jan 2013

Approximation By Iterates Of Beta Operators, Purshottam Narain Agrawal, Karunesh Kumar Singh, Vikas Kumar Mishra

Turkish Journal of Mathematics

In this paper, we study the degree of approximation by an iterative combination T_{n,k} of the beta operators introduced by Upreti [8].


Generating Systems Of Differential Invariants And The Theorem On Existence For Curves In The Pseudo-Euclidean Geometry}, Djavvat Khadjiev, İdri̇s Ören, Ömer Pekşen Jan 2013

Generating Systems Of Differential Invariants And The Theorem On Existence For Curves In The Pseudo-Euclidean Geometry}, Djavvat Khadjiev, İdri̇s Ören, Ömer Pekşen

Turkish Journal of Mathematics

Let M(n, p) be the group of all motions of an n-dimensional pseudo-Euclidean space of index p. It is proved that the complete system of M(n,p)-invariant differential rational functions of a path (curve) is a generating system of the differential field of all M(n,p)-invariant differential rational functions of a path (curve), respectively. A fundamental system of relations between elements of the complete system of M(n,p)-invariant differential rational functions of a path (curve) is described.


Global And Finitistic Dimension Of Hopf-Galois Extensions, Ling Liu, Qiaoling Guo Jan 2013

Global And Finitistic Dimension Of Hopf-Galois Extensions, Ling Liu, Qiaoling Guo

Turkish Journal of Mathematics

Let H be a Hopf algebra over a field k and A/B a right H-Galois extension. Then in this note a spectral sequence for Ext will be constructed which yields the estimate for global dimension of A in terms of the corresponding data for H and B. As an application, we obtain the Maschke-type theorems for crossed products and twisted smash products. Finally, the relationship of finitistic dimensions between A and B will be given, if H is semisimple.


Existence And Multiplicity Of Positive Solutions For A Class Of Nonlinear Elliptic Problems, Asadollah Aghajani, Jamile Shamshiri, Frajollah Mohammadi Yaghoobi Jan 2013

Existence And Multiplicity Of Positive Solutions For A Class Of Nonlinear Elliptic Problems, Asadollah Aghajani, Jamile Shamshiri, Frajollah Mohammadi Yaghoobi

Turkish Journal of Mathematics

We study the existence and multiplicity of nonnegative solutions for the nonlinear elliptic problem, -\Delta u+v(x)u=a(x)u^p+\lambda f(x,u) for x\in\Omega and u=0 on \partial\Omega, where \Omega is a bounded region in R^N, N>2, 1


On The Maximal Operators Of Vilenkin-Fejéer Means, George Tephnadze Jan 2013

On The Maximal Operators Of Vilenkin-Fejéer Means, George Tephnadze

Turkish Journal of Mathematics

The main aim of this paper is to prove that the maximal operator \overset{\sim}{\sigma}^{\ast}f:=\underset{n \in P} \sup\frac{ \sigma _nf }{\log^2 (n+1)} is bounded from the Hardy space H_{1/2} to the space L_{1/2}, where \sigma _nf are Fejér means of bounded Vilenkin-Fourier series.


Sasakian Finsler Manifolds, Ayşe Funda Yaliniz, Nesri̇n Çalişkan Jan 2013

Sasakian Finsler Manifolds, Ayşe Funda Yaliniz, Nesri̇n Çalişkan

Turkish Journal of Mathematics

In this study, almost contact Finsler structures on vector bundle are defined and the condition of normality in terms of the Nijenhuis torsion N_{\phi} of almost contact Finsler structure is obtained. It is shown that for a K-contact structure on Finsler manifold \nabla_X \xi =-\frac{1}{2} \phi X and the flag curvature for plane sections containing \xi are equal to \frac{1}{4}. By using the Sasakian Finsler structure, the curvatures of a Finsler connection \nabla on V are obtained. We prove that a locally symmetric Finsler manifold with K-contact Finsler structure has a constant curvature \frac{1}{4}. Also, the Ricci curvature on Finsler …