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2013

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Articles 781 - 810 of 1053

Full-Text Articles in Mathematics

Oscillation Of Solutions Of A Neutral Pantograph Equation With Impulsive Perturbations, Kaizhong Guan Jan 2013

Oscillation Of Solutions Of A Neutral Pantograph Equation With Impulsive Perturbations, Kaizhong Guan

Turkish Journal of Mathematics

Some sufficient conditions are established on the oscillation of all solutions of a class of neutral pantograph equations with impulsive perturbations of the form \{\begin{array}{l}\frac{d}{dt}[x(t)-C(t)x(\gamma t)]+ \frac{P(t)}{t}x(\alpha t)-\frac{Q(t)}{t}x(\beta t)=0,~~ t\geq t_{0}>0,~~ t\neq t_{k}, x(t^{+}_{k})=b_{k}x(t_{k}), k=1,2,... . \end{array}\right.

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Blow-Up Phenomena For Nonlocal Inhomogeneous Diffusion Problems, Jianwen Sun, Feiying Yang Jan 2013

Blow-Up Phenomena For Nonlocal Inhomogeneous Diffusion Problems, Jianwen Sun, Feiying Yang

Turkish Journal of Mathematics

This paper is concerned with the blow-up of solutions to some nonlocal inhomogeneous dispersal equations subject to homogeneous Neumann boundary conditions. We establish conditions on nonlinearities sufficient to guarantee that solutions exist for all time as well as blow up at some finite time. Moreover, lower bounds for blow-up time of nonlocal problems are obtained.

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Commutants And Hyper-Reflexivity Of Multiplication Operators, Masoumeh Faghih Ahmadi, Karim Hedayatian Jan 2013

Commutants And Hyper-Reflexivity Of Multiplication Operators, Masoumeh Faghih Ahmadi, Karim Hedayatian

Turkish Journal of Mathematics

We characterize the commutants of some multiplication operators on a Banach space of analytic functions defined on a bounded domain in the plane. Under certain conditions on the symbol of a multiplication operator, we show that its commutant is a set of multiplication operators. This partially answers a question of Axler, Cuckovic and Rao. Next, the hyper-reflexivity of these multiplication operators are proved. The paper is concluded by proving the hyper-reflexivity of the multiplication operators with symbols \varphi (z) = z^k, k=1, 2,... .

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On The Non-Propagation Theorem And Applications, Nassim Athmouni, Mondher Damak Jan 2013

On The Non-Propagation Theorem And Applications, Nassim Athmouni, Mondher Damak

Turkish Journal of Mathematics

We use C^*-algebras to determine the non-propagation estimates for a certain class of generalized Schrödinger operators acting on the Hilbert space \ell^2(\Gamma), where \Gamma is a tree, and we give some examples for other classes of potentials.

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Lie Groupoids And Generalized Almost Paracomplex Manifolds, Fulya Şahi̇n, Mustafa Habi̇l Gürsoy, İlhan İçen Jan 2013

Lie Groupoids And Generalized Almost Paracomplex Manifolds, Fulya Şahi̇n, Mustafa Habi̇l Gürsoy, İlhan İçen

Turkish Journal of Mathematics

In this paper, we show that there is a close relationship between generalized paracomplex manifolds and Lie groupoids. We obtain equivalent assertions among the integrability conditions of generalized almost paracomplex manifolds, the condition of compatibility of source and target maps of symplectic groupoids with symplectic form and generalized paraholomorphic maps.

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Threshold Complexes And Connections To Number Theory, Jonathan Pakianathan, Troy Winfree Jan 2013

Threshold Complexes And Connections To Number Theory, Jonathan Pakianathan, Troy Winfree

Turkish Journal of Mathematics

In this paper we study quota complexes (or equivalently in the case of scalar weights, threshold complexes) and how the topology of these quota complexes changes as the quota is changed. This problem is a simple ``linear\" version of the general question in Morse Theory of how the topology of a space varies with a parameter. We give examples of natural and basic quota complexes where this problem frames questions about the distribution of primes, squares and divisors in number theory and as an example provide natural topological formulations of the prime number theorem, the twin prime conjecture, Goldbach's conjecture, …

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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.

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Erratum To: ``Null Mannheim Curves In The Minkowski 3-Space E_1^3'', Handan Özteki̇n, Mahmut Ergüt Jan 2013

Erratum To: ``Null Mannheim Curves In The Minkowski 3-Space E_1^3'', Handan Özteki̇n, Mahmut Ergüt

Turkish Journal of Mathematics

In this paper, Theorem 3.2 and Proposition 3.2 in the paper which is cited in the title are corrected.

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Radical Operations On The Multiplicative Lattice, Esra Şengelen Sevi̇m Jan 2013

Radical Operations On The Multiplicative Lattice, Esra Şengelen Sevi̇m

Turkish Journal of Mathematics

The purpose of this paper is to introduce interesting and useful properties of quasi-radical and radical operations on the elements of a multiplicative lattice.

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Polynomial Root Separation In Terms Of The Remak Height, Arturas Dubickas Jan 2013

Polynomial Root Separation In Terms Of The Remak Height, Arturas Dubickas

Turkish Journal of Mathematics

We investigate some monic integer irreducible polynomials which have two close roots. If P(x) is a separable polynomial in Z[x] of degree d \geq 2 with the Remak height R(P) and the minimal distance between the quotient of two distinct roots and unity Sep(P), then the inequality 1/Sep(P) \ll R(P)^{d-1} is true with the implied constant depending on d only. Using a recent construction of Bugeaud and Dujella we show that for each d \geq 3 there exists an irreducible monic polynomial P \in Z[x] of degree d for which R(P)^{(2d-3)(d-1)/(3d-5)} \ll 1/Sep(P). For d=3 the exponent 3/2 is improved …

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Finite Groups With Some Weakly S-Supplementally Embedded Subgroups, Tao Zhao Jan 2013

Finite Groups With Some Weakly S-Supplementally Embedded Subgroups, Tao Zhao

Turkish Journal of Mathematics

A subgroup H of G is said to be weakly s-supplementally embedded in G if there exist a subgroup T of G and an s-permutably embedded subgroup H_{se} of G contained in H such that G=HT and H \cap T \leq H_{se}. In this paper, we investigate the influence of some weakly s-supplementally embedded subgroups on the structure of a finite group G. Some earlier results are unified and generalized.

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A Characterization Of Auslander Category, Juxiang Sun Jan 2013

A Characterization Of Auslander Category, Juxiang Sun

Turkish Journal of Mathematics

In this paper, we discuss the Bass class and the Auslander class with respect to a semidualizing module over an associative ring. Let _SC_R be a semidualizing module, we proved that the Bass class B_C (R) is a right orthogonal subcategory of some right R-module; and that the Auslander class A_C (S) is a left orthogonal subcategory of the character module of some left S-module. As an application, we introduce the notion of the minimal semidualizing module, and get a one to one correspondence between the isomorphism classes of minimal semidualizing R-modules and maximal classes among coresolving preenvelope classes of …

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Surgery In Codimension 3 And The Browder--Livesay Invariants, Friedrich Hegenbarth, Yuri Muranov, Dusan Repovs Jan 2013

Surgery In Codimension 3 And The Browder--Livesay Invariants, Friedrich Hegenbarth, Yuri Muranov, Dusan Repovs

Turkish Journal of Mathematics

The inertia subgroup I_n(\pi) of a surgery obstruction group L_n(\pi) is generated by elements that act trivially on the set of homotopy triangulations S(X) for some closed topological manifold X^{n-1} with \pi_1(X) = \pi. This group is a subgroup of the group C_n(\pi), which consists of the elements that can be realized by normal maps of closed manifolds. These 2 groups coincide by a recent result of Hambleton, at least for n \geq 6 and in all known cases. In this paper we introduce a subgroup J_n(\pi) \subset I_n(\pi), which is generated by elements of the group L_n(\pi), which act …

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Morphism Classes Producing (Weak) Grothendieck Topologies, (Weak) Lawvere--Tierney Topologies, And Universal Closure Operations, Seyed Naser Hosseini, Mehdi Nodehi Jan 2013

Morphism Classes Producing (Weak) Grothendieck Topologies, (Weak) Lawvere--Tierney Topologies, And Universal Closure Operations, Seyed Naser Hosseini, Mehdi Nodehi

Turkish Journal of Mathematics

In this article, given a category X, with \Omega the subobject classifier in Set^{X^{op}, we set up a one-to-one correspondence between certain (i) classes of X-morphisms, (ii) \Omega-subpresheaves, (iii) \Omega-automorphisms, and (iv) universal operators. As a result we give necessary and sufficient conditions on a morphism class so that the associated (i) \Omega-subpresheaf is a (weak) Grothendieck topology, (ii) \Omega-automorphism is a (weak) Lawvere--Tierney topology, and (iii) universal operation is an (idempotent) universal closure operation. We also finally give several examples of morphism classes yielding (weak) Grothendieck topologies, (weak) Lawvere--Tierney topologies, and (idempotent) universal closure operations.

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On The Minkowski Measurability Of Self-Similar Fractals In R^D, Ali̇ Deni̇z, Mehmet Şahi̇n Koçak, Yunus Özdemi̇r, Andrei̇ Rati̇u, Adem Ersi̇n Üreyen Jan 2013

On The Minkowski Measurability Of Self-Similar Fractals In R^D, Ali̇ Deni̇z, Mehmet Şahi̇n Koçak, Yunus Özdemi̇r, Andrei̇ Rati̇u, Adem Ersi̇n Üreyen

Turkish Journal of Mathematics

The question of Minkowski measurability of fractals is investigated for different situations by various authors, notably by M. Lapidus. In dimension one it is known that the attractor of an IFS consisting of similitudes (and satisfying a certain open set condition) is Minkowski measurable if and only if the IFS is of non-lattice type and it was conjectured that this would be true also in higher dimensions. Half of this conjecture was proved by Gatzouras in 2000, who showed that the attractor of an IFS (satisfying the open set condition) is Minkowski measurable if the IFS is of non-lattice type. …

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Quasinormability And Diametral Dimension, Ahmet Tosun Terzi̇oğlu Jan 2013

Quasinormability And Diametral Dimension, Ahmet Tosun Terzi̇oğlu

Turkish Journal of Mathematics

Two versions of diametral dimension are shown to coincide for quasinormable Fréchet spaces. The diametral dimension is determined by a single bounded subset in certain cases.

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Complete Cotorsion Pairs In The Category Of Complexes, Zhanping Wang, Zhongkui Liu Jan 2013

Complete Cotorsion Pairs In The Category Of Complexes, Zhanping Wang, Zhongkui Liu

Turkish Journal of Mathematics

In this paper, we study completeness of cotorsion pairs in the category of complexes of R-modules. Let (A, B) be a cotorsion pair in R-Mod. It is shown that the cotorsion pair (\widetilde{A}, dg\widetilde{B}) and (\overline{A}, \overline{A}^{\perp}) are complete if A is closed under pure submodules and cokernels of pure monomorphisms, where in Gillespie's definitions \widetilde{A} is the class of exact complexes with cycles in A and dg\widetilde{B} is the class of complexes X with components in B such that the complex Hom(A, X) is exact for every complex A \in \widetilde{A}; and \overline{A} is the class of all complexes …

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Slant Submersions From Almost Product Riemannian Manifolds, Yilmaz Gündüzalp Jan 2013

Slant Submersions From Almost Product Riemannian Manifolds, Yilmaz Gündüzalp

Turkish Journal of Mathematics

In this paper, we define the concept of almost product Riemannian submersion between almost product Riemannian manifolds. We introduce slant submersions from almost product Riemannian manifolds onto Riemannian manifolds. We give examples and investigate the geometry of foliations that arise from the definition of a Riemannian submersion. We also find necessary and sufficient conditions for a slant submersion to be totally geodesic.

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Factorization Of Composite Polynomials Over Finite Fields, Saeid Mehrabi Jan 2013

Factorization Of Composite Polynomials Over Finite Fields, Saeid Mehrabi

Turkish Journal of Mathematics

This paper presents the reducibility of some composite polynomials and explicitly determines the factorization over finite fields. Also families of irreducible polynomials over finite fields are introduced.

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Remarks On The Paper ``On Some New Inequalities For Convex Functions\\" By M. Tunç, Alfred Witkowski Jan 2013

Remarks On The Paper ``On Some New Inequalities For Convex Functions\\" By M. Tunç, Alfred Witkowski

Turkish Journal of Mathematics

In this note, we slightly generalize Theorem 2 in the paper by M. Tunç and point out that the assumption of Theorem 3 is not sufficient. A misuse of the term 'mean' is also discussed.

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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 …

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On The Existence Of Nonzero Injective Covers And Projective Envelopes Of Modules, Xiaoxiang Zhang, Xianmei Song Jan 2013

On The Existence Of Nonzero Injective Covers And Projective Envelopes Of Modules, Xiaoxiang Zhang, Xianmei Song

Turkish Journal of Mathematics

In general, the injective cover (projective envelope) of a simple module can be zero. A ring R is called a weakly left V-ring (strongly left Kasch ring) if every simple left R-module has a nonzero injective cover (projective envelope). It is proven that every nonzero left R-module has a nonzero injective cover if and only if R is a left Artinian weakly left V-ring. Dually, every nonzero left R-module has a nonzero projective envelope if and only if R is a left perfect right coherent strongly left Kasch ring. Some related rings and examples are considered.

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On The Krull Dimension Of Endo-Bounded Modules, Ahmad Haghany, Majid Mazrooei, Mohamad Reza Vedadi Jan 2013

On The Krull Dimension Of Endo-Bounded Modules, Ahmad Haghany, Majid Mazrooei, Mohamad Reza Vedadi

Turkish Journal of Mathematics

Modules in which every essential submodule contains an essential fully invariant submodule are called endo-bounded. Let M be a nonzero module over an arbitrary ring R and X = Spec_2(M_R), the set of all fully invariant L_2-prime submodules of M_R. If M_R is a quasi-projective L_2-Noetherian such that (M/P)_R is endo-bounded for any P \in X, then it is shown that the Krull dimension of M_R is at most the classical Krull dimension of the poset X. The equality of these dimensions and some applications are obtained for certain modules. This gives a generalization of a well-known result on right …

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On The Pollard Decomposition Method Applied To Some Jacobi--Sobolev Expansions, Francisco Marcellán, Yamilet Quintana, Alejandro Urieles Jan 2013

On The Pollard Decomposition Method Applied To Some Jacobi--Sobolev Expansions, Francisco Marcellán, Yamilet Quintana, Alejandro Urieles

Turkish Journal of Mathematics

Let {q_n^{(\alpha,\beta)}}_{n \geq 0} be the sequence of polynomials orthonormal with respect to the Sobolev inner product \langle f,g\rangle_S:=\int_{-1}^1f(x)g(x)w^{(\alpha,\beta)}(x)dx+\int_{-1}^1f'(x)g'(x)w^{(\alpha+1,\beta+1)}(x)dx, where w^{(\alpha,\beta)}(x)=(1-x)^{\alpha}(1+x)^{\beta}, x\in [-1,1] and \alpha,\beta>-1. This paper explores the convergence in the W^{1,p}\left((-1,1), (w^{(\alpha,\beta)},w^{(\alpha+1,\beta+1)})\right) norm of the Fourier expansion in terms of {q_n^{(\alpha,\beta)}}_{n\geq 0} with 1< p

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Complemented Invariant Subspaces Of Structural Matrix Algebras, Mustafa Akkurt, Emi̇ra Akkurt, George Phillip Barker Jan 2013

Complemented Invariant Subspaces Of Structural Matrix Algebras, Mustafa Akkurt, Emi̇ra Akkurt, George Phillip Barker

Turkish Journal of Mathematics

In this paper, we explore when the lattice of invariant subspaces of a structural matrix algebra can be complemented. We give several equivalent conditions for this lattice to be a Boolean algebra.

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Magnetic Field-Induced Stability Of A Specific Configuration And The Asymptotic Behavior Of Minimizers In Nematic Liquid Crystals, Junichi Aramaki Jan 2013

Magnetic Field-Induced Stability Of A Specific Configuration And The Asymptotic Behavior Of Minimizers In Nematic Liquid Crystals, Junichi Aramaki

Turkish Journal of Mathematics

We consider the stability of a specific nematic liquid crystal configuration under an applied magnetic field. We impose the strong anchoring condition, and we allow the boundary data to be nonconstant and also the applied field to be nonconstant. Thus, we shall extend the results of Lin and Pan in 2007. We show that for some specific configuration there exist 2 critical values H_n and H_{sh} of applied magnetic field. When the intensity of the magnetic field is smaller than H_n, the configuration of the energy is only a global minimizer, when the intensity is between H_n and H_{sh}, the …

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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.

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Colombeau Solutions Of A Nonlinear Stochastic Predator--Prey Equation, Uluğ Çapar Jan 2013

Colombeau Solutions Of A Nonlinear Stochastic Predator--Prey Equation, Uluğ Çapar

Turkish Journal of Mathematics

The solution of a random semilinear hyperbolic system with singular initial data is sought as a random Colombeau distribution. The product of 2 additive white noises is well tackled within the theory of random Colombeau distributions. In the special case of a random predator--prey system, the exact Colombeau solution is obtained under some assumptions when the process is driven by doubly reflected Brownian motions.

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Some Results On Cyclic Codes Over The Ring R_{2,M}, Reza Sobhani, Maryam Molakarimi Jan 2013

Some Results On Cyclic Codes Over The Ring R_{2,M}, Reza Sobhani, Maryam Molakarimi

Turkish Journal of Mathematics

Let R_{k,m} be the ring F_{2^m}[u_1,u_2,...,u_k]/\gen u_i^2, u_iu_j-u_ju_i. In this paper, cyclic codes of arbitrary length n over the ring R_{2,m} are completely characterized in terms of unique generators and a way for determination of these generators is investigated. A F_{2^m}-basis for these codes is also derived from this representation. Moreover, it is proven that there exists a one-to-one correspondence between cyclic codes of length 2n, n odd, over the ring R_{k-1,m} and cyclic codes of length n over the ring R_{k,m}. By determining the complete structure of cyclic codes of length 2 over R_{2,m}, a mass formula for the …

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Strong Solution For A High Order Boundary Value Problem With Integral Condition, Ahcene Merad, Ahmed Lakhdar Marhoune Jan 2013

Strong Solution For A High Order Boundary Value Problem With Integral Condition, Ahcene Merad, Ahmed Lakhdar Marhoune

Turkish Journal of Mathematics

The present paper is devoted to a proof of the existence and uniqueness of strong solution for a high order boundary value problem with integral condition. The proof is based by a priori estimate and on the density of the range of the operator generated by the studied problem.

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