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2017

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Articles 991 - 1020 of 1334

Full-Text Articles in Mathematics

Generalized $\Ast$-Lie Ideal Of $\Ast$-Prime Ring, Seli̇n Türkmen, Neşet Aydin Jan 2017

Generalized $\Ast$-Lie Ideal Of $\Ast$-Prime Ring, Seli̇n Türkmen, Neşet Aydin

Turkish Journal of Mathematics

Let $R$ be a $\ast$-prime ring with characteristic not $2,$ $\sigma, \tau:R\rightarrow R$ be two automorphisms, $U$ be a nonzero $\ast$-$\left( \sigma,\tau\right) $-Lie ideal of $R$ such that $\tau~$commutes with $\ast$, and $a,b$ be in $R.$ $\left( i\right) $ If $a\in S_{\ast}\left( R\right) $ and $\left[ U,a\right] =0$, then $a\in Z\left( R\right) $ or $U\subset Z\left( R\right) .$ $\left( ii\right) $ If $a\in S_{\ast}\left( R\right) $ and $\left[ U,a\right] _{\sigma,\tau}\subset$ $C_{\sigma,\tau}$, then $a\in Z\left( R\right) ~$or$~U\subset Z\left( R\right) .$ $\left( iii\right) $ If $U\not \subset Z\left( R\right) $ and $U\not \subset C_{\sigma,\tau}$, then there exists a nonzero $\ast$-ideal $M$ of …

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Graph-Directed Fractal Interpolation Functions, Ali̇ Deni̇z, Yunus Özdemi̇r Jan 2017

Graph-Directed Fractal Interpolation Functions, Ali̇ Deni̇z, Yunus Özdemi̇r

Turkish Journal of Mathematics

It is known that there exists a function interpolating a given data set such that the graph of the function is the attractor of an iterated function system, which is called a fractal interpolation function. We generalize the notion of the fractal interpolation function to the graph-directed case and prove that for a finite number of data sets there exist interpolation functions each of which interpolates a corresponding data set in $\mathbb{R}^2$ such that the graphs of the interpolation functions are attractors of a graph-directed iterated function system.

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Coefficient Bounds For A New Subclass Of Analytic Bi-Close-To-Convex Functions By Making Use Of Faber Polynomial Expansion, Fethi̇ye Müge Sakar, Hatun Özlem Güney Jan 2017

Coefficient Bounds For A New Subclass Of Analytic Bi-Close-To-Convex Functions By Making Use Of Faber Polynomial Expansion, Fethi̇ye Müge Sakar, Hatun Özlem Güney

Turkish Journal of Mathematics

Recently, in the literature, we can see quite a few papers about general coefficient bounds for subclasses of bi-univalent functions. However, we can find just a few papers about general coefficient estimates for subclasses of bi-close-to-convex functions. In the present study, we give and look into a new subclass of analytic and bi-close-to-convex functions in the open unit disk. Making use of the Faber series, we have an upper bound for the general coefficient of functions in this class. We also demonstrate the invisible behavior of the beginning coefficients of a special subclass of bi-close-to-convex functions.

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On The Stochastic Decomposition Property Of Single Server Retrialqueuing Systems, Nawel Arrar, Natalia Djellab, Jean-Bernard Baillon Jan 2017

On The Stochastic Decomposition Property Of Single Server Retrialqueuing Systems, Nawel Arrar, Natalia Djellab, Jean-Bernard Baillon

Turkish Journal of Mathematics

The study of retrial queuing systems presents great analytical difficulties. Detailed results are available for some models, whereas for other models the obtained results revealed poor information and are cumbersome (they contain Laplace transforms, integral expressions, etc.). Therefore, in practice, they present limited performance. Often, to overcome this difficulty, we use an approach based on the stochastic decomposition property that can be possessed by the model. It offers the advantages of simplification of solving complex models. This paper deals with the stochastic decomposition property of an M$^{X}$/G/1 retrial queue with impatient customers and exponential retrial times and of an M/G/1 …

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Singular Dirac Systems In The Sobolev Space, Eki̇n Uğurlu Jan 2017

Singular Dirac Systems In The Sobolev Space, Eki̇n Uğurlu

Turkish Journal of Mathematics

In this paper we construct Weyl's theory for the singular left-definite Dirac systems. In particular, we prove that there exists at least one solution of the system of equations that lies in the Sobolev space. Moreover, we describe the behavior of the solution belonging to the Sobolev space around the singular point.

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On Golden Semisymmetric Metric $F$-Connections, Aydin Gezer, Çağri Karaman Jan 2017

On Golden Semisymmetric Metric $F$-Connections, Aydin Gezer, Çağri Karaman

Turkish Journal of Mathematics

In this paper, we construct a golden semisymmetric metric $F$-connection on a locally decomposable golden Riemannian manifold and investigate some properties of its curvature, conharmonic curvature, Weyl projective curvature, and torsion tensors. Moreover, we define the transposed connection of this connection and study its curvature properties.

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Cardinal Hermite Interpolant Multiscaling Functions For Solving A Parabolic Inverse Problem, Elmira Ashpazzadeh, Mehrdad Lakestani, Mohsen Razzaghi Jan 2017

Cardinal Hermite Interpolant Multiscaling Functions For Solving A Parabolic Inverse Problem, Elmira Ashpazzadeh, Mehrdad Lakestani, Mohsen Razzaghi

Turkish Journal of Mathematics

An effective method based upon cardinal Hermite interpolant multiscaling functions is proposed for the solution of the one-dimensional parabolic partial differential equation with given initial condition and known boundary conditions and subject to overspecification at a point in the spatial domain. The properties of multiscaling functions are first presented. These properties together with a collocation method are then utilized to reduce the parabolic inverse problem to the solution of algebraic equations. The scheme described is efficient. The numerical results obtained using the present algorithms for test problems show that this method can solve the model effectively.

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Finite Volume Approximation Of The Relativistic Burgers Equation On A Schwarzschild-(Anti-)De Sitter Spacetime, Tuba Ceylan, Baver Okutmuştur Jan 2017

Finite Volume Approximation Of The Relativistic Burgers Equation On A Schwarzschild-(Anti-)De Sitter Spacetime, Tuba Ceylan, Baver Okutmuştur

Turkish Journal of Mathematics

The relativistic versions of Burgers equations on the Schwarzschild, FLRW, and de Sitter backgrounds have recently been derived and analyzed numerically via finite volume approximation based on the concerned models. In this work, we derive the relativistic Burgers equation on a Schwarzschild-(anti-)de Sitter spacetime and introduce a second-order Godunov-type finite volume scheme for the approximation of discontinuous solutions to the model of interest. The effect of the cosmological constant is also taken into account both theoretically and numerically. The efficiency of the method for solutions containing shock and rarefaction waves are presented by several numerical experiments.

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Almost Contact Metric Structures Induced By $G_2$ Structures, Nüli̇fer Özdemi̇r, Mehmet Solgun, Şi̇ri̇n Aktay Jan 2017

Almost Contact Metric Structures Induced By $G_2$ Structures, Nüli̇fer Özdemi̇r, Mehmet Solgun, Şi̇ri̇n Aktay

Turkish Journal of Mathematics

We study almost contact metric structures induced by 2-fold vector cross products on manifolds with $G_2$ structures. We get some results on possible classes of almost contact metric structures. Finally, we give examples.

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On $\Lambda$-Perfect Maps, Mehrdad Namdari, Mohammad Ali Siavoshi Jan 2017

On $\Lambda$-Perfect Maps, Mehrdad Namdari, Mohammad Ali Siavoshi

Turkish Journal of Mathematics

$\lambda$-Perfect maps, a generalization of perfect maps (i.e. continuous closed maps with compact fibers) are presented. Using $P_\lambda$-spaces and the concept of $\lambda$-compactness some classical results regarding $\lambda$-perfect maps will be extended. In particular, we show that if the composition $fg$ is a $\lambda$-perfect map where $f,g$ are continuous maps with $fg$ well-defined, then $f,g$ are $\alpha$-perfect and $\beta$-perfect, respectively, on appropriate spaces, where $\alpha, \beta\leq\lambda$.

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Terminal Value Problem For Causal Differential Equations With A Caputofractional Derivative, Coşkun Yakar, Mehmet Arslan Jan 2017

Terminal Value Problem For Causal Differential Equations With A Caputofractional Derivative, Coşkun Yakar, Mehmet Arslan

Turkish Journal of Mathematics

In this paper, we have given new definitions and obtained the unique solution of a fractional causal terminal value problem by combining the technique of generalized quasilinearization in the sense of upper and lower solutions.

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Some Theorems For A New Type Of Multivalued Contractivemaps On Metric Space, Gonca Durmaz Jan 2017

Some Theorems For A New Type Of Multivalued Contractivemaps On Metric Space, Gonca Durmaz

Turkish Journal of Mathematics

In this paper, taking into account the function $\theta $, we introduce a new type of contraction for multivalued maps on metric space. This new concept includes many known contractions in the literature. We then present some fixed point results for closed and bounded set valued maps on complete metric space. Finally, we provide an example to show the significance of the investigation of this paper.

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Permutation Groups With Cyclic-Block Property And $Mnfc$-Groups, Ali̇ Osman Asar Jan 2017

Permutation Groups With Cyclic-Block Property And $Mnfc$-Groups, Ali̇ Osman Asar

Turkish Journal of Mathematics

This work continues the investigation of perfect locally finite minimal non-$FC$-groups in totally imprimitive permutation $p$-groups. At present, the class of totally imprimitive permutation $p$-groups satisfying the cyclic-block property is known to be the only class of $p$-groups having common properties with a hypothetical minimal non-$FC$-group, because a totally imprimitive permutation $p$-group satisfying the cyclic-block property cannot be generated by a subset of finite exponent and every non-$FC$-subgroup of it is transitive, which are the properties satisfied by a minimal non-$FC$-group. Here a sufficient condition is given for the nonexistence of minimal non-$FC$-groups in this class of permutation groups. In …

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Positive Periodic Solutions To Impulsive Delay Differentialequations, Naima Daoudi-Merzagui, Fatima Dib Jan 2017

Positive Periodic Solutions To Impulsive Delay Differentialequations, Naima Daoudi-Merzagui, Fatima Dib

Turkish Journal of Mathematics

In this paper we discuss the existence of positive periodic solutions for nonautonomous second order delay differential equations with singular nonlinearities in the presence of impulsive effects. Simple sufficient conditions are provided that enable us to obtain positive periodic solutions. Our approach is based on a variational method.

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Unicorn Metrics With Almost Vanishing ${\Bf H}$- And ${\Bf \Xi}$-Curvatures, Akbar Tayebi, Tayebeh Tabatabaeifar Jan 2017

Unicorn Metrics With Almost Vanishing ${\Bf H}$- And ${\Bf \Xi}$-Curvatures, Akbar Tayebi, Tayebeh Tabatabaeifar

Turkish Journal of Mathematics

In this paper, we consider a class of almost regular $(\alpha, \beta)$-metrics constructed by Shen called unicorn metrics. First, we prove that every unicorn metric with almost vanishing ${\bf H}$-curvature is a Berwald metric. Then we show that every unicorn metric with almost vanishing $\Xi$-curvature reduces to a Berwald metric.

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On The 3-Dimensional Hopf Bifurcation Via Averaging Theory Of Third Order, Elouahma Bendib, Sabrina Badi, Ammar Makhlouf Jan 2017

On The 3-Dimensional Hopf Bifurcation Via Averaging Theory Of Third Order, Elouahma Bendib, Sabrina Badi, Ammar Makhlouf

Turkish Journal of Mathematics

We apply the averaging theory of third order to polynomial quadratic vector fields in $\mathbb{R}^3$ to study the Hopf bifurcation occurring in that polynomial. Our main result shows that at most $10$ limit cycles can bifurcate from a singular point having eigenvalues of the form $\pm bi$ and $0$. We provide an example of a quadratic polynomial differential system for which exactly $10$ limit cycles bifurcate from a such singular point.

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Subspace Condition For Bernstein's Lethargy Theorem, Asuman Güven Aksoy, Monairah Al-Ansari, Caleb Case, Qidi Peng Jan 2017

Subspace Condition For Bernstein's Lethargy Theorem, Asuman Güven Aksoy, Monairah Al-Ansari, Caleb Case, Qidi Peng

Turkish Journal of Mathematics

In this paper, we consider a condition on subspaces in order to improve bounds given in Bernstein's lethargy theorem for Banach spaces. Let $d_1 \geq d_2 \geq \dots d_n \geq \dots > 0$ be an infinite sequence of numbers converging to $0$, and let $Y_1 \subset Y_2 \subset \dots\subset Y_n \subset \dots \subset X$ be a sequence of closed nested subspaces in a Banach space $X$ with the property that $\overline{Y}_{n}\subset Y_{n+1}$ for all $n\ge1$. We prove that for any $c ın (0,1]$ there exists an element $x_c ın X$ such that$$ c d_n \leq \rho(x_c, Y_n) \leq \min (4, \tilde{a}) …

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Schanuel's Lemma, The Snake Lemma, And Product And Direct Sum In $H_V$-Modules, Yaser Vaziri, Mansour Ghadiri Jan 2017

Schanuel's Lemma, The Snake Lemma, And Product And Direct Sum In $H_V$-Modules, Yaser Vaziri, Mansour Ghadiri

Turkish Journal of Mathematics

In this paper we find a generalization of the snake lemma and Schanuel's lemma in $H_v$-modules. We define the isomorph sequences and determine the conditions to split the exact sequences in $H_v$-modules. Some interesting results on these concepts are given.

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The Ptolemaean Inequality In The Closure Of Complex Hyperbolic Planes, Ioannis D. Platis, Ni̇lgün Sönmez Jan 2017

The Ptolemaean Inequality In The Closure Of Complex Hyperbolic Planes, Ioannis D. Platis, Ni̇lgün Sönmez

Turkish Journal of Mathematics

We prove the Ptolemaean inequality andPtolemaeus' theorem in the closure of complex hyperbolic planes endowed with theCygan metric.

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Some Results On Uniform Statistical Cluster Points, Tuğba Yurdakadi̇m, Leila Miller-Van Wieren Jan 2017

Some Results On Uniform Statistical Cluster Points, Tuğba Yurdakadi̇m, Leila Miller-Van Wieren

Turkish Journal of Mathematics

In this paper, we present some results linking the uniform statistical limit superior and inferior, almost convergence and uniform statistical convergence of a sequence.We also study the relationship between the set of uniform statistical cluster points of a given sequence and its subsequences. The resultsconcerning uniform statistical convergence and uniform statistical cluster points presented here are also closelyrelated to earlier results regarding statistical convergence and statistical cluster points of a sequence.

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New Inequalities Of Opial Type For Conformable Fractional Integrals, Mehmet Zeki̇ Sarikaya, Hüseyi̇n Budak Jan 2017

New Inequalities Of Opial Type For Conformable Fractional Integrals, Mehmet Zeki̇ Sarikaya, Hüseyi̇n Budak

Turkish Journal of Mathematics

In this paper, some Opial-type inequalities for conformable fractionalintegrals are obtained using the remainder function of Taylor's theorem forconformable integrals.

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Meromorphic Function And Its Difference Operator Share Two Sets With Weight K, Bingmao Deng, Dan Liu, Degui Yang Jan 2017

Meromorphic Function And Its Difference Operator Share Two Sets With Weight K, Bingmao Deng, Dan Liu, Degui Yang

Turkish Journal of Mathematics

In this paper, we utilize Nevanlinna value distribution theory to study the uniqueness problem that a meromorphic function and its difference operator share two sets with weight $k$. Our results extend the previous results.

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The Role Of The Ideal Elements In Studying The Structure Of Some Ordered Semigroups, Niovi Kehayopulu Jan 2017

The Role Of The Ideal Elements In Studying The Structure Of Some Ordered Semigroups, Niovi Kehayopulu

Turkish Journal of Mathematics

The aim of writing this paper is given in the title. We want to show that not only the ideals but also the ideal elements play an essential role in studying the structure of some ordered semigroups.We first prove that a $\vee e$-semigroup $S$ is a semilattice of left simple $\vee e$-semigroups if and only if it is decomposable into some pairwise disjoint left simple $\vee e$-subsemigroups of $S$ indexed by a semilattice $Y$. Then we give an example of a semilattice of left simple $\vee e$-semigroups that leads to a characterization of the semilattices of left simple and the …

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Character Analogue Of The Boole Summation Formula With Applications, Mümün Can, Muhammet Ci̇hat Dağli Jan 2017

Character Analogue Of The Boole Summation Formula With Applications, Mümün Can, Muhammet Ci̇hat Dağli

Turkish Journal of Mathematics

In this paper, we present the character analogue of the Boole summationformula. Using this formula, an integral representation is derived for thealternating Dirichlet $L$-function and its derivative is evaluated at $s=0$.Some applications of the character analogue of the Boole summation formula andthe integral representation are given about the alternating Dirichlet $L$-function. Moreover, the reciprocity formulas for two new arithmetic sums,arising from the summation formulas, and for Hardy--Berndt sum $S_{p}(b,c:\chi)$ are proved.

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Depth And Stanley Depth Of The Path Ideal Associated To An $N$-Cyclic Graph, Guangjun Zhu Jan 2017

Depth And Stanley Depth Of The Path Ideal Associated To An $N$-Cyclic Graph, Guangjun Zhu

Turkish Journal of Mathematics

We compute the depth and Stanley depth for the quotient ringof the path ideal of length $3$ associated to a $n$-cyclic graph, given some precise formulas for the depth when $n\not\equiv 1\,(\mbox{mod}\ 4)$, tight bounds when $n\equiv 1\,(\mbox{mod}\ 4)$,and for Stanley depth when $n\equiv 0,3\,(\mbox{mod}\ 4)$, tight bounds when $n\equiv 1,2\,(\mbox{mod}\ 4)$. We also give some formulas forthe depth and Stanley depth of a quotient of the path ideals of length $n-1$ and $n$.

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A Note On Locally Graded Minimal Non-Metahamiltonian Groups, Sevgi̇ Atlihan Jan 2017

A Note On Locally Graded Minimal Non-Metahamiltonian Groups, Sevgi̇ Atlihan

Turkish Journal of Mathematics

We prove that a nonperfect locally gradedminimal non-metahamiltonian group $G$ is a soluble group withderived length of at most 4. On the other hand, if $G$ is perfect,then $G/\Phi (G)$ is isomorphic to $A_{5}$, where $\Phi (G)$ isthe Frattini subgroup of $G$ and $A_{5}$ is the alternating group.Moreover, we show that under some conditions,if G is a $p$-group, then G is metabelian, where $p$ is a prime integer.

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Some Properties Of Alternate Duals And Approximate Alternate Duals Of Fusion Frames, Ali Akbar Arefijamaal, Fahimeh Arabyani Neyshaburi Jan 2017

Some Properties Of Alternate Duals And Approximate Alternate Duals Of Fusion Frames, Ali Akbar Arefijamaal, Fahimeh Arabyani Neyshaburi

Turkish Journal of Mathematics

In this paper we extend the notion of approximate dual to fusion frames and present some approaches to obtain alternate dual and approximate alternate dual fusion frames. We also study the stability of alternate dual and approximate alternate dual fusion frames.

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A New Approach To Uniqueness For Inverse Sturm-Liouville Problems On Finite Intervals, Seyfollah Mosazadeh Jan 2017

A New Approach To Uniqueness For Inverse Sturm-Liouville Problems On Finite Intervals, Seyfollah Mosazadeh

Turkish Journal of Mathematics

In this paper, an approach for studying inverse Sturm--Liouville problems with integrable potentials on finite intervals is presented. We find the relations between Weyl solutions and $m_{j}$-functions of Sturm--Liouville problems, and by finding the connection between these and the solutions of second-order partial differential equations for transformation kernels associated with Sturm--Liouville operators, we prove the uniqueness of the solution of inverse problems.

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A Characterization Of Nonprime Powers, Raul Duran Diaz, Luis Hernandez Encinas, Agustin Martin Muñoz, Jaime Muñoz Masque, Seok-Zun Song Jan 2017

A Characterization Of Nonprime Powers, Raul Duran Diaz, Luis Hernandez Encinas, Agustin Martin Muñoz, Jaime Muñoz Masque, Seok-Zun Song

Turkish Journal of Mathematics

A criterion is presented in order to decide whether agiven integer is a prime power or not. The criterion associatesto each positive integer $m$ a finite set of integers$\mathcal{S}(m)$, each of them $\le m $ and the propertiesof this set are studied. The notion of complementary pairsin $\mathcal{S}(m)$ is introduced and it is proved that if one isable to determine a complementary pair $n,n^\prime $, thena partial factorization of the odd integer $m$ can be obtainedin polynomial time. Some particular cases and examples of these resultsare given.

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Stationary Distribution And Global Asymptotic Stability Of A Three-Species Stochastic Food-Chain System, Hong Qiu, Wenmin Deng Jan 2017

Stationary Distribution And Global Asymptotic Stability Of A Three-Species Stochastic Food-Chain System, Hong Qiu, Wenmin Deng

Turkish Journal of Mathematics

This paper intends to study some dynamical properties of a stochasticthree-dimensional Lotka--Volterra system. Under some mild assumptions, we first introduce a simple method to show thatthe model has a global and positive solution almost surely. Secondly,we prove that this model has a stationary distribution. Then we study the global asymptoticstability of the positive solution. Finally, some numerical simulations are introduced toillustrate the theoretical results.

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