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2015

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Articles 841 - 870 of 1160

Full-Text Articles in Mathematics

Good Modulating Sequences For The Ergodic Hilbert Transform, Azer Akhmedov, Doğan Çömez Jan 2015

Good Modulating Sequences For The Ergodic Hilbert Transform, Azer Akhmedov, Doğan Çömez

Turkish Journal of Mathematics

This article investigates classes of bounded sequences of complex numbers that are universally good for the ergodic Hilbert transform in L_p-spaces, 2 \leq p \leq \infty. The class of bounded Besicovitch sequences satisfying a rate condition is among such sequence classes.

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On Separating Subadditive Maps, Vesko Valov Jan 2015

On Separating Subadditive Maps, Vesko Valov

Turkish Journal of Mathematics

Recall that a map T \colon C(X,E) \to C(Y,F), where X, Y are Tychonoff spaces and E, F are normed spaces, is said to be separating, if for any 2 functions f,g \in C(X,E) we have c(T(f)) \cap c(T(g))= \varnothing provided c(f) \cap c(g) = \varnothing. Here c(f) is the co-zero set of f. A typical result generalizing the Banach--Stone theorem is of the following type (established by Araujo): if T is bijective and additive such that both T and T^{-1} are separating, then the realcompactification \nu X of X is homeomorphic to \nu Y. In this paper we show …

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Coextended Weak Entwining Structures, José Nicanor Alonso Álvarez, José Manuel Fernandez Vilaboa, Ramón González Rodríguez Jan 2015

Coextended Weak Entwining Structures, José Nicanor Alonso Álvarez, José Manuel Fernandez Vilaboa, Ramón González Rodríguez

Turkish Journal of Mathematics

In this paper, we formulate the definition of coextended weak entwining structure in a strict monoidal category with equalizers. For a coextended weak entwining structure (A,D,\psi,\alpha), we introduce the notions of weak (D,\alpha)-cleft extension and weak (D,\alpha)-Galois extension (with normal basis), proving that weak (D,\alpha)-Galois extensions with normal basis are equivalent to weak (D,\alpha)-cleft extensions.

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Companion Inequalities To Ostrowski--Grüss Type Inequality And Applications, Khalid Mahmood Awan, Josip Pecaric, Mihaela Ribicic Penava Jan 2015

Companion Inequalities To Ostrowski--Grüss Type Inequality And Applications, Khalid Mahmood Awan, Josip Pecaric, Mihaela Ribicic Penava

Turkish Journal of Mathematics

The aim of this paper is to give some companion inequalities to the Ostrowski-Grüss type inequality for n-time differentiable absolutely continuous functions by using recently obtained bounds for the Chebyshev functional.

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Spreading Speeds In A Lattice Differential Equation With Distributed Delay, Huiling Niu Jan 2015

Spreading Speeds In A Lattice Differential Equation With Distributed Delay, Huiling Niu

Turkish Journal of Mathematics

This paper studies the spreading speed for a lattice differential equation with infinite distributed delay and we find that the spreading speed coincides with the minimal wave speed of traveling waves. Here the model has been proposed to describe a single species living in a 1D patch environment with infinite number of patches connected locally by diffusion.

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Some Remarks On Distributional Chaos For Bounded Linear Operators, Lvlin Luo, Bingzhe Hou Jan 2015

Some Remarks On Distributional Chaos For Bounded Linear Operators, Lvlin Luo, Bingzhe Hou

Turkish Journal of Mathematics

The aim of this paper is to study distributional chaos for bounded linear operators. We show that distributional chaos of type k \in {1,2} is an invariant of topological conjugacy between two bounded linear operators. We give a necessary condition for distributional chaos of type 2 where it is possible to distinguish distributional chaos and Li--Yorke chaos. Following this condition, we compare distributional chaos with other well-studied notions of chaos for backward weighted shift operators and give an alternative proof to the one where strong mixing does not imply distributional chaos of type 2 (Martínez-Giménez F, Oprocha P, Peris A. …

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The Geometry Of Hemi-Slant Submanifolds Of A Locally Product Riemannian Manifold, Hakan Mete Taştan, Fatma Özdemi̇r Jan 2015

The Geometry Of Hemi-Slant Submanifolds Of A Locally Product Riemannian Manifold, Hakan Mete Taştan, Fatma Özdemi̇r

Turkish Journal of Mathematics

In the present paper, we study hemi-slant submanifolds of a locally product Riemannian manifold. We prove that the anti-invariant distribution involved in the definition of hemi-slant submanifold is integrable and give some applications of this result. We get a necessary and sufficient condition for a proper hemi-slant submanifold to be a hemi-slant product. We also study these types of submanifolds with parallel canonical structures. Moreover, we give two characterization theorems for the totally umbilical proper hemi-slant submanifolds. Finally, we obtain a basic inequality involving Ricci curvature and the squared mean curvature of a hemi-slant submanifold of a certain type of …

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The Fundamental Theorems Of Algebroid Functions On Annuli, Yang Tan, Qingcai Zhang Jan 2015

The Fundamental Theorems Of Algebroid Functions On Annuli, Yang Tan, Qingcai Zhang

Turkish Journal of Mathematics

An extension of Nevanlinna value distribution theory for algebroid functions on annuli is proposed. The main characteristics are one-parameter and possess the same properties as in the classical case. Analogs of the Cartan theorem, the first fundamental theorem, the second fundamental theorem, deficient values, and the uniqueness of algebroid functions on annuli are proved.

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Real Hypersurfaces In Complex Two-Plane Grassmannians Whose Shape Operator Is Recurrent For The Generalized Tanaka-Webster Connection, Juan De Dios Perez, Young Jin Suh, Changhwa Woo Jan 2015

Real Hypersurfaces In Complex Two-Plane Grassmannians Whose Shape Operator Is Recurrent For The Generalized Tanaka-Webster Connection, Juan De Dios Perez, Young Jin Suh, Changhwa Woo

Turkish Journal of Mathematics

We prove the non-existence of Hopf real hypersurfaces in complex two-plane Grassmannians whose shape operator $A$ is generalized Tanaka-Webster recurrent if the principal curvature of the structure vector field is not equal to trace(A).

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Almost Analytic Forms With Respect To A Quadratic Endomorphism And Their Cohomology, Mircea Crasmareanu, Cristian Ida Jan 2015

Almost Analytic Forms With Respect To A Quadratic Endomorphism And Their Cohomology, Mircea Crasmareanu, Cristian Ida

Turkish Journal of Mathematics

The goal of this paper is to consider the notion of almost analytic form in a unifying setting for both almost complex and almost paracomplex geometries. We use a global formalism, which yields, in addition to generalizations of the main results of the previously known almost complex case, a relationship with the Frölicher-Nijenhuis theory. A cohomology of almost analytic forms is also introduced and studied as well as deformations of almost analytic forms with pairs of almost analytic functions.

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On Broyden-Like Update Via Some Quadratures For Solving Nonlinear Systems Of Equations, Hassan Mohammad, Mohammed Yusuf Waziri Jan 2015

On Broyden-Like Update Via Some Quadratures For Solving Nonlinear Systems Of Equations, Hassan Mohammad, Mohammed Yusuf Waziri

Turkish Journal of Mathematics

In this work, we propose a new alternative approximation based on the quasi-Newton approach for solving systems of nonlinear equations using the average of midpoint and Simpson's quadrature. Our goal is to enhance the efficiency of the method (Broyden's method) by reducing the number of iterations it takes to reach a solution. Local convergence analysis and computational results showing the relative efficiency of the proposed method are given.

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Finite Groups With Three Conjugacy Class Sizes Of Primary And Biprimary Elements, Changguo Shao, Qinhui Jiang Jan 2015

Finite Groups With Three Conjugacy Class Sizes Of Primary And Biprimary Elements, Changguo Shao, Qinhui Jiang

Turkish Journal of Mathematics

We determine the structure of finite $\pi(m)$-separable groups if the set of conjugacy class sizes of primary and biprimary elements is $\{1, m, mn\}$, where $m$ and $n$ are two coprime integers.

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On Some Classes Of $3$-Dimensional Generalized $ (\Kappa ,\Mu )$-Contact Metric Manifolds, Ahmet Yildiz, Uday Chand De, Azi̇me Çeti̇nkaya Jan 2015

On Some Classes Of $3$-Dimensional Generalized $ (\Kappa ,\Mu )$-Contact Metric Manifolds, Ahmet Yildiz, Uday Chand De, Azi̇me Çeti̇nkaya

Turkish Journal of Mathematics

The object of the present paper is to obtain a necessary and sufficient condition for a $3$-dimensional generalized $(\kappa ,\mu )$-contact metric manifold to be locally $\phi $-symmetric in the sense of Takahashi and the condition is verified by an example. Next we characterize a $3$-dimensional generalized $(\kappa ,\mu )$-contact metric manifold satisfying certain curvature conditions on the concircular curvature tensor. Finally, we construct an example of a generalized $(\kappa,\mu)$-contact metric manifold to verify Theorem $1$ of our paper.

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Regular Poles For The P-Adic Group $Gsp_4$-Ii, Yusuf Danişman Jan 2015

Regular Poles For The P-Adic Group $Gsp_4$-Ii, Yusuf Danişman

Turkish Journal of Mathematics

We compute the regular poles of the L-factors of the admissible and irreducible representations of the group $GSp_4$, which admit a nonsplit Bessel functional and have a Jacquet module length of 3 with respect to the unipotent radical of the Siegel parabolic, over a non-Archimedean local field of odd characteristic. We also compute the $L$-factors of the generic representations of $GSp_4$.

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Characterizing Rational Groups Whose Irreducible Characters Vanish Only On Involutions, Saeed Jafari, Hesam Sharifi Jan 2015

Characterizing Rational Groups Whose Irreducible Characters Vanish Only On Involutions, Saeed Jafari, Hesam Sharifi

Turkish Journal of Mathematics

A rational group is a finite group whose irreducible complex characters are rational valued. The aim of this paper is to classify rational groups $G$ for which every nonlinear irreducible character vanishes only on involutions.

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Notes On Magnetic Curves In 3d Semi-Riemannian Manifolds, Zehra Özdemi̇r, İsmai̇l Gök, Yusuf Yayli, Fai̇k Nejat Ekmekci̇ Jan 2015

Notes On Magnetic Curves In 3d Semi-Riemannian Manifolds, Zehra Özdemi̇r, İsmai̇l Gök, Yusuf Yayli, Fai̇k Nejat Ekmekci̇

Turkish Journal of Mathematics

A magnetic field is defined by the property that its divergence is zero in three-dimensional semi-Riemannian manifolds. Each magnetic field generates a magnetic flow whose trajectories are curves $\gamma $, called magnetic curves. In this paper, we investigate the effect of magnetic fields on the moving particle trajectories by variational approach to the magnetic flow associated with the Killing magnetic field on three-dimensional semi-Riemannian manifolds. We then investigate the trajectories of these magnetic fields and give some characterizations and examples of these curves.

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Stability In A Job Market With Linearly Increasing Valuations And Quota System, Yasir Ali Jan 2015

Stability In A Job Market With Linearly Increasing Valuations And Quota System, Yasir Ali

Turkish Journal of Mathematics

We consider a job market in which preferences of players are represented by linearly increasing valuations. The set of players is divided into two disjoint subsets: a set of workers and a set of firms. The set of workers is further divided into subsets, which represent different categories or classes in everyday life. We consider that firms have vacant posts for all such categories. Each worker wants a job for a category to which he/she belongs. Firms have freedom to hire more than one worker from any category. A worker can work in only one category for at most one …

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Rational Schubert Polynomials, Kürşat Aker, Nesri̇n Tutaş Jan 2015

Rational Schubert Polynomials, Kürşat Aker, Nesri̇n Tutaş

Turkish Journal of Mathematics

We define and study the rational Schubert, rational Grothendieck, rational key polynomials in an effort to understand Molev's dual Schur functions from the viewpoint of Lascoux.

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Warped Product Skew Semi-Invariantsubmanifolds Of Order $1$ Of A Locallyproduct Riemannian Manifold, Hakan Mete Taştan Jan 2015

Warped Product Skew Semi-Invariantsubmanifolds Of Order $1$ Of A Locallyproduct Riemannian Manifold, Hakan Mete Taştan

Turkish Journal of Mathematics

We introduce warped product skew semi-invariant submanifolds of order $1$ of a locally product Riemannian manifold. We give a necessary and sufficient condition for a skew semi-invariant submanifold of order 1 to be a locally warped product. We also establish an inequality between the warping function and the squared norm of the second fundamental form for such submanifolds. The equality case is also discussed.

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Invariant Distributions And Holomorphic Vector Fields In Paracontact Geometry, Mircea Crasmareanu, Laurian Ioan Piscoran Jan 2015

Invariant Distributions And Holomorphic Vector Fields In Paracontact Geometry, Mircea Crasmareanu, Laurian Ioan Piscoran

Turkish Journal of Mathematics

Having as a model the metric contact case of V. Brînzănescu; R. Slobodeanu, we study two similar subjects in the paracontact (metric) geometry: a) distributions that are invariant with respect to the structure endomorphism $\varphi $; b) the class of vector fields of holomorphic type. As examples we consider both the $3$-dimensional case and the general dimensional case through a Heisenberg-type structure inspired also by contact geometry.

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On Zeros Of Certain Dirichlet Polynomials, Kajtaz H. Bllaca Jan 2015

On Zeros Of Certain Dirichlet Polynomials, Kajtaz H. Bllaca

Turkish Journal of Mathematics

In this article we establish the zero-free region of certain Dirichlet polynomials $L_{F, X}$ arising in approximate functional equation for functions in the Selberg class and we prove an asymptotic formula for the number of zeros of $L_{F, X}$.

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Stability Of Compact Ricci Solitons Under Ricci Flow, Mina Vaghef, Asadollah Razavi Jan 2015

Stability Of Compact Ricci Solitons Under Ricci Flow, Mina Vaghef, Asadollah Razavi

Turkish Journal of Mathematics

In this paper we establish stability results for Ricci solitons under the Ricci flow, i.e. small perturbations of the Ricci soliton result in small variations in the solution under Ricci flow.

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A Note On M-Embedded Subgroups Of Finite Groups, Juping Tang, Long Miao Jan 2015

A Note On M-Embedded Subgroups Of Finite Groups, Juping Tang, Long Miao

Turkish Journal of Mathematics

Let $A$ be a subgroup of $G$. $A$ is m-embedded in $G$ if $G$ has a subnormal subgroup $T$ and a $\{1\leq G\}$-embedded subgroup $C$ such that $G=AT$ and $T\cap A\leq C\leq A$. In this paper, we study the structure of finite groups by using m-embedded subgroups and obtain some new results about $p$-supersolvability and $p$-nilpotency of finite groups. \vs{-1mm}

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Approximate Duals And Nearly Parseval Frames, Morteza Mirzaee Azandaryani Jan 2015

Approximate Duals And Nearly Parseval Frames, Morteza Mirzaee Azandaryani

Turkish Journal of Mathematics

In this paper we introduce approximate duality of g-frames in Hilbert $C^\ast$-modules and we show that approximate duals of g-frames in Hilbert $C^\ast$-modules share many useful properties with those in Hilbert spaces. Moreover, we obtain some new results for approximate duality of frames and g-frames in Hilbert spaces; in particular, we consider approximate duals of $\varepsilon$-nearly Parseval and $\varepsilon$-close frames.

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Random Process Generated By The Incomplete Gauss Sums, Emek Demi̇rci̇ Akarsu Jan 2015

Random Process Generated By The Incomplete Gauss Sums, Emek Demi̇rci̇ Akarsu

Turkish Journal of Mathematics

In this paper we explore a random process generated by the incomplete Gauss sums and establish an analogue of weak invariance principle for these sums. We focus our attention exclusively on a generalization of the limit distribution of the long incomplete Gauss sums given by the family of periodic functions analyzed by the author and Marklof.

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Some Identities For The Glasser Transform And Their Applications, Faruk Uçar Jan 2015

Some Identities For The Glasser Transform And Their Applications, Faruk Uçar

Turkish Journal of Mathematics

In the present paper we consider a new integral transform, denoted by $\mathcal{G}_{\nu}$, which may be regarded as a generalization of the well-known transform due to Glasser. Many identities involving this transform are given. By making use of these identities, a number of new Parseval--Goldstein type identities are obtained for these and many other well-known integral transforms. The identities proven in this paper are shown to give rise to useful corollaries for evaluating infinite integrals of special functions. Some examples are also given as illustrations of the results presented here.

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On The Computation Of Generalized Division Polynomials, Ömer Küçüksakalli Jan 2015

On The Computation Of Generalized Division Polynomials, Ömer Küçüksakalli

Turkish Journal of Mathematics

We give an algorithm to compute the generalized division polynomials for elliptic curves with complex multiplication. These polynomials can be used to generate the ray class fields of imaginary quadratic fields over the Hilbert class field with no restriction on the conductor.

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Existence Of Solutions For A First-Order Nonlocal Boundary Value Problem With Changing-Sign Nonlinearity, Erbi̇l Çeti̇n, Fatma Serap Topal Jan 2015

Existence Of Solutions For A First-Order Nonlocal Boundary Value Problem With Changing-Sign Nonlinearity, Erbi̇l Çeti̇n, Fatma Serap Topal

Turkish Journal of Mathematics

This work is concerned with the existence of positive solutions to a nonlinear nonlocal first-order multipoint problem. Here the nonlinearity is allowed to take on negative values, not only positive values.

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On Certain Minimal Non-$\Mathfrak{Y}$-Groups For Some Classes $\Mathfrak{Y}$, Ahmet Arikan, Selami̇ Ercan Jan 2015

On Certain Minimal Non-$\Mathfrak{Y}$-Groups For Some Classes $\Mathfrak{Y}$, Ahmet Arikan, Selami̇ Ercan

Turkish Journal of Mathematics

Let $\{\theta_n\}_{n=1}^\infty$ be a sequence of words. If there exists a positive integer $n$ such that $\theta_m(G)=1$ for every $m\geq n$, then we say that $G$ satisfies (*) and denote the class of all groups satisfying (*) by $\mathfrak{X}_{\{\theta_n\}_{n=1}^\infty}$. If for every proper subgroup $K$ of $G$, $K\in \mathfrak{X}_{\{\theta_n\}_{n=1}^\infty}$ but $G\notin\mathfrak{X}_{\{\theta_n\}_{n=1}^\infty}$, then we call $G$ a minimal non-$\mathfrak{X}_{\{\theta_n\}_{n=1}^\infty}$-group. Assume that $G$ is an infinite locally finite group with trivial center and $\theta_i(G)=G$ for all $i\geq 1$. In this case we mainly prove that there exists a positive integer $t$ such that for every proper normal subgroup $N$ of $G$, either …

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The Prime Tournaments $T$ With $\Mid\! W_{5}(T) \!\Mid = \Mid\! T \!\Mid -2$, Houmem Belkhechine, Imed Boudabbous, Kaouthar Hzami Jan 2015

The Prime Tournaments $T$ With $\Mid\! W_{5}(T) \!\Mid = \Mid\! T \!\Mid -2$, Houmem Belkhechine, Imed Boudabbous, Kaouthar Hzami

Turkish Journal of Mathematics

We consider a tournament $T=(V, A)$. For $X\subseteq V$, the subtournament of $T$ induced by $X$ is $T[X] = (X, A \cap (X \times X))$. A module of $T$ is a subset $X$ of $V$ such that for $a, b\in X$ and $ x\in V\setminus X$, $(a,x)\in A$ if and only if $(b,x)\in A$. The trivial modules of $T$ are $\emptyset$, $\{x\}(x\in V)$, and $V$. A tournament is prime if all its modules are trivial. For $n\geq 2$, $W_{2n+1}$ denotes the unique prime tournament defined on $\{0,\dots,2n\}$ such that $W_{2n+1}[\{0,\dots,2n-1\}]$ is the usual total order. Given a prime tournament $T$, …

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