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

Digital Commons Network™

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

Articles 1891 - 1920 of 2781

Full-Text Articles in Entire DC Network

A Note On Chaos In Product Maps, Risong Li, Xiaoliang Zhou Jan 2013

A Note On Chaos In Product Maps, Risong Li, Xiaoliang Zhou

Turkish Journal of Mathematics

In this paper, we mainly discuss how chaos conditions on semi-flows carry over to their products. We show that if two semi-flows (or even one of them) are sensitive, so does their product. On the other side, the product of two topologically transitive semi-flows need not be topologically transitive. We then provide several sufficient conditions under which the product of two chaotic semi-flows is chaotic in the sense of Devaney. Also, stronger forms of sensitivity and transitivity for product systems are studied. In particular, we introduce the notion of ergodic sensitivity and prove that for any given two (not-necessarily continuous) …


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


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


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


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 …


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 …


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.


A Scheme Over Prime Spectrum Of Modules, Ahmad Abbasi, Dawood Hassanzadeh Lelekami Jan 2013

A Scheme Over Prime Spectrum Of Modules, Ahmad Abbasi, Dawood Hassanzadeh Lelekami

Turkish Journal of Mathematics

Let R be a commutative ring with nonzero identity and let M be an R-module with X=Spec(M). It is introduced a scheme O_X on the prime spectrum of M and some of its properties have been investigated.


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.


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.


New Trace Formula For The Matrix Sturm-Liouville Equation With Eigenparameter Dependent Boundary Conditions, Chuan Fu Yang Jan 2013

New Trace Formula For The Matrix Sturm-Liouville Equation With Eigenparameter Dependent Boundary Conditions, Chuan Fu Yang

Turkish Journal of Mathematics

A regularized trace formula of first order for the matrix Sturm-Liouville equation with eigenparameter in the boundary conditions is obtained.


Contact 3-Structure Qr-Warped Product Submanifold In Sasakian Space Form, Esmaiel Abedi, Ghorbanali Haghighatdoost, Mohammad Ilmakchi, Zahra Nazari Jan 2013

Contact 3-Structure Qr-Warped Product Submanifold In Sasakian Space Form, Esmaiel Abedi, Ghorbanali Haghighatdoost, Mohammad Ilmakchi, Zahra Nazari

Turkish Journal of Mathematics

In the present paper we obtain sharp estimates for the squared norm of the second fundamental form in terms of the mapping function for contact 3-structure CR-warped products isometrically immersed in Sasakian space form.


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.


Finite Rings And Wilson's Theorem, Yasuyuki Hirano, Manabu Matsuoka Jan 2013

Finite Rings And Wilson's Theorem, Yasuyuki Hirano, Manabu Matsuoka

Turkish Journal of Mathematics

In this paper we consider the product of all elements in the group of units in a finite ring and we generalize Wilson's theorem to finite rings. As an application, we study some generalizations of Wilson's theorem on residually finite Dedekind domains. And we also give some examples for such rings. Moreover we study some generalizations of Wilson's theorem on rings of matrices over a finite commutative ring.


On Theta Pair For A Proper Subalgebra, Ali Reza Salemkar, Sara Chehrazi, Hamid Mohammadzadeh Jan 2013

On Theta Pair For A Proper Subalgebra, Ali Reza Salemkar, Sara Chehrazi, Hamid Mohammadzadeh

Turkish Journal of Mathematics

For a proper subalgebra K of a finite dimensional Lie algebra L, a pair (A,B) of subalgebras of L is called a \theta-pair if L = \langle A,K\rangle, B is the largest ideal of L contained in A\cap K and for each proper subalgebra C/B of A/B which is an ideal of L/B, we have L\neq C+K. In this article, using this concept, we give some characterizations of solvability and supersolvability of a finite dimensional Lie algebra.


C.P. Modules And Their Applications, Qiongling Liu, Jianlong Chen Jan 2013

C.P. Modules And Their Applications, Qiongling Liu, Jianlong Chen

Turkish Journal of Mathematics

Let R be a ring. A left R-module M is called a c.p. module if every cyclic submodule of M is projective. This notion is a generalization of left p.p. rings in the general module theoretic setting. The aim of this article is to investigate these modules. Some characterizations and properties are given. As applications, the connections among Baer rings, p.p. rings and von Neumann regular rings are studied.


Integral Polytopes And Polynomial Factorization, Fati̇h Koyuncu Jan 2013

Integral Polytopes And Polynomial Factorization, Fati̇h Koyuncu

Turkish Journal of Mathematics

For any field F, there is a relation between the factorization of a polynomial f \in F[x_1,...,x_n] and the integral decomposition of the Newton polytope of f. We extended this result to polynomial rings R[x_1,...,x_n] where R is any ring containing some elements which are not zero-divisors. Moreover, we have constructed some new families of integrally indecomposable polytopes in \mb giving infinite families of absolutely irreducible multivariate polynomials over arbitrary fields.


A Nonlocal Parabolic Problem In An Annulus For The Heaviside Function In Ohmic Heating, Fei Liang, Hongjun Gao, Charles Bu Jan 2013

A Nonlocal Parabolic Problem In An Annulus For The Heaviside Function In Ohmic Heating, Fei Liang, Hongjun Gao, Charles Bu

Turkish Journal of Mathematics

In this paper, we consider the nonlocal parabolic equation u_t=\Delta u+\frac{\lambda H(1-u)}{\big(\int_{A_{\rho, R}} H(1-u)dx\big)^2}, x\in A_{\rho, R} \subset R^2, t>0, with a homogeneous Dirichlet boundary condition, where \lambda is a positive parameter, H is the Heaviside function and A_{\rho, R} is an annulus. It is shown for the radial symmetric case that: there exist two critical values \lambda_* and \lambda^*, so that for 0


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].


On Characterization And Stability Of Alternate Dual Of G-Frames, Ali Akbar Arefijamaal, Soheila Ghasemi Jan 2013

On Characterization And Stability Of Alternate Dual Of G-Frames, Ali Akbar Arefijamaal, Soheila Ghasemi

Turkish Journal of Mathematics

One of the essential applications of frames is that they lead to expansions of vectors in the underlying Hilbert space in terms of the frame elements. In this decomposition, dual frames have a key role. G-frames, introduced by Sun, cover many other recent generalizations of frames. In this paper, we give some characterizations of dual g-frames. Moreover, we prove that if two g-frames are close to each other, then we can find duals of them which are close to each other.


Scalar Curvature And Symmetry Properties Of Lightlike Submanifolds}, Cyriaque Atindogbe, Oscar Lungiambudila, Joel Tossa Jan 2013

Scalar Curvature And Symmetry Properties Of Lightlike Submanifolds}, Cyriaque Atindogbe, Oscar Lungiambudila, Joel Tossa

Turkish Journal of Mathematics

In this paper, the induced Ricci tensor and the extrinsic scalar curvature on lightlike submanifolds are obtained. This scalar quantity extend the result given by C. Atindogbe in [1]. An example of extrinsic scalar curvature on one class of 2-degenerate manifolds is provided. We investigate lightlike submanifolds which are locally symmetric, semi-symmetric, Ricci semi-symmetric in indefinite spaces form. In the coisotropic case, we show that, under some conditions, these lightlike submanifolds are totally geodesic.


Paracontact Semi-Riemannian Submersions, Yilmaz Gündüzalp, Bayram Şahi̇n Jan 2013

Paracontact Semi-Riemannian Submersions, Yilmaz Gündüzalp, Bayram Şahi̇n

Turkish Journal of Mathematics

In this paper, we first define the concept of paracontact semi-Riemannian submersions between almost paracontact metric manifolds, then we provide an example and show that the vertical and horizontal distributions of such submersions are invariant with respect to the almost paracontact structure of the total manifold. The study is focused on fundamental properties and the transference of structures defined on the total manifold. Moreover, we obtain various properties of the O'Neill's tensors for such submersions and find the integrability of the horizontal distribution. We also find necessary and sufficient conditions for a paracontact semi-Riemannian submersion to be totally geodesic. Finally, …


Asymptotics Of The Ruin Probability With Claims Modeled By \\Alpha-Stable Aggregated Ar(1) Process, Karina Perilioglu, Donata Puplinskaite Jan 2013

Asymptotics Of The Ruin Probability With Claims Modeled By \\Alpha-Stable Aggregated Ar(1) Process, Karina Perilioglu, Donata Puplinskaite

Turkish Journal of Mathematics

We study the asymptotics of the ruin probability in a discrete time risk insurance model with stationary claims following the aggregated heavy-tailed AR(1) process discussed in Puplinskaite and Surgailis (2010). The present work is based on the general characterization of the ruin probability with claims modeled by stationary \alpha-stable process in Mikosch and Samorodnitsky (2000). We prove that for the aggregated AR(1) claims' process, the ruin probability decays with exponent \alpha(1-H), where H \in [1/\alpha, 1) is the asymptotic self-similarity index of the claim process, 1< \alpha < 2. This result agrees with the decay rate of the ruin probability with claims modeled by increments of linear fractional motion in Mikosch and Samorodnitsky (2000) and also with other characterizations of long memory of the aggregated AR(1) process with infinite variance in Puplinskaite and Surgailis (2010).


Braiding For Internal Categories In The Category Of Whiskered Groupoids And Simplicial Groups, Erdal Ulualan, Sedat Pak Jan 2013

Braiding For Internal Categories In The Category Of Whiskered Groupoids And Simplicial Groups, Erdal Ulualan, Sedat Pak

Turkish Journal of Mathematics

In this work, we define the notion of `braiding' for an internal groupoid in the category of whiskered groupoids and we give a relation between this structure and simplicial groups by using higher order Peiffer elements in the Moore complex of a simplicial group.


Generalized Class Invariants With `Thetanullwerte\', Osmanbey Uzunkol Jan 2013

Generalized Class Invariants With `Thetanullwerte\', Osmanbey Uzunkol

Turkish Journal of Mathematics

We introduce generalized class invariants as quotients of Thetanullwerte, which realize the computation of class polynomials more efficiently than as quotients of values of the Dedekind \eta-function. Furthermore, we prove that these invariants are units in the corresponding class field as most of their classical counterparts.


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.


The Total Graph Of A Finite Commutative Ring, Ali Ramin Jan 2013

The Total Graph Of A Finite Commutative Ring, Ali Ramin

Turkish Journal of Mathematics

Let R be a commutative ring with Z(R), its set of zero-divisors and \mbox{Reg}(R), its set of regular elements. Total graph of R, denoted by T(\Gamma(R)), is the graph with all elements of R as vertices, and two distinct vertices x,y \in R, are adjacent in T(\Gamma(R)) if and only if x+y \in Z(R). In this paper, some properties of T(\Gamma(R)) have been investigated, where R is a finite commutative ring and a new upper bound for vertex-connectivity has been obtained in this case. Also, we have proved that the edge-connectivity of T(\Gamma(R)) coincides with the minimum degree if and …


Derived And Residual Sylvester-Hadamard Designs And The Smith Normal Form, İlhan Hacioğlu Jan 2013

Derived And Residual Sylvester-Hadamard Designs And The Smith Normal Form, İlhan Hacioğlu

Turkish Journal of Mathematics

We computed the Smith normal form of Sylvester-Hadamard designs and its complement, their derived and residual Sylvester-Hadamard designs and their complementary derived and residual Sylvester-Hadamard designs.


A Variation Of Supplemented Modules, Gökhan Bi̇lhan, Ayşe Tugba Güroğlu Jan 2013

A Variation Of Supplemented Modules, Gökhan Bi̇lhan, Ayşe Tugba Güroğlu

Turkish Journal of Mathematics

Over a general ring, an R-module is w-supplemented if and only if amply w-supplemented. It is proved that over a local Dedekind domain, all modules are w-supplemented and over a non-local Dedekind domain, an R-module M is w-supplemented if and only if Soc(M)\ll M or M=S_0 \oplus (\bigoplus_{i \in I} K), where S_0 is a torsion, semisimple submodule of M and K is the field of quotients of R.