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2020

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Articles 1171 - 1200 of 1326

Full-Text Articles in Mathematics

Units And 2-Class Field Towers Of Some Multiquadratic Number Fields, Mohamed Mahmoud Chems-Eddin, Abdelkader Zekhnini, Abdelmalek Azizi Jan 2020

Units And 2-Class Field Towers Of Some Multiquadratic Number Fields, Mohamed Mahmoud Chems-Eddin, Abdelkader Zekhnini, Abdelmalek Azizi

Turkish Journal of Mathematics

In this paper, we investigate the unit groups, the 2-class groups, the 2-class field towers and the structures of the second 2-class groups of some multiquadratic number fields of degree 8 and 16.


On 3-Dimensional Almost Einstein Manifolds With Circulant Structures, Iva Dokuzova Jan 2020

On 3-Dimensional Almost Einstein Manifolds With Circulant Structures, Iva Dokuzova

Turkish Journal of Mathematics

A 3-dimensional Riemannian manifold equipped with a tensor structure of type (1,1), whose third power is the identity, is considered. This structure and the metric have circulant matrices with respect to some basis, i.e. these structures are circulant. An associated manifold, whose metric is expressed by both structures, is studied. Three classes of such manifolds are considered. Two of them are determined by special properties of the curvature tensor of the manifold. The third class is composed by manifolds whose structure is parallel with respect to the Levi-Civitaconnection of the metric. Some geometric characteristics of these manifolds are obtained. Examples …


On Ulam's Type Stability Criteria For Fractional Integral Equations Including Hadamard Type Singular Kernel, Yasemi̇n Başci, Süleyman Öğrekçi̇, Adi̇l Misir Jan 2020

On Ulam's Type Stability Criteria For Fractional Integral Equations Including Hadamard Type Singular Kernel, Yasemi̇n Başci, Süleyman Öğrekçi̇, Adi̇l Misir

Turkish Journal of Mathematics

In this paper, we deal with the Hyers-Ulam-Rassias (HUR) and Hyers-Ulam (HU) stability of Hadamard type fractional integral equations on compact intervals. The stability conditions are developed using a new generalized metric (GM) definition and the fixed point technique by motivating Wang and Lin Ulam's type stability of Hadamard type fractional integral equations. Filomat 2014; 28(7): 1323-1331. Moreover, our approach is efficient and ease in use than to the previously studied approaches. Finally, we give two examples to explain our main results.


Asymptotic Socle Behaviors For Cones Over Curves In Positive Characteristic, Jinjia Li Jan 2020

Asymptotic Socle Behaviors For Cones Over Curves In Positive Characteristic, Jinjia Li

Turkish Journal of Mathematics

This paper studies the distribution of socle degrees of $R/I^{[p^e]}$ when $e$ is large, for a homogeneous ideal $I$ in a two-dimensional standard-graded normal domain $R$ in positive characteristic $p$. We prove that the distribution is very much related to the asymptotic slopes of the syzygy bundle Syz$(I)$, which have been known to determine the Hilbert-Kunz multiplicity of $I$.


The Meyer Function On The Handlebody Group, Yusuke Kuno, Masatoshi Sato Jan 2020

The Meyer Function On The Handlebody Group, Yusuke Kuno, Masatoshi Sato

Turkish Journal of Mathematics

We give an explicit formula for the signature of handlebody bundles over the circle interms of the homological monodromy. This gives a cobounding function of Meyer's signature cocycle on the mapping class group of a 3-dimensional handlebody, i.e. the handlebody group. As an application, we give a topological interpretation for the generator of the first cohomology group of the hyperelliptic handlebody group.


On Quasi-Affinity And Reducing Subspaces Of Multiplication Operator On A Certain Closed Subspace, Yucheng Li, Lina Song, Wenhua Lan Jan 2020

On Quasi-Affinity And Reducing Subspaces Of Multiplication Operator On A Certain Closed Subspace, Yucheng Li, Lina Song, Wenhua Lan

Turkish Journal of Mathematics

Let $H$ denote a certain closed subspace of the Bergman space $A_{\alpha}^{2}({\B}_{n})(\alpha>-1)$ of the unit ball in $\mathbb{C}^{n}$. In this paper, we prove that the operator $\bigoplus\limits_{1}^{m}M_{z^{(s_{1},\cdots,s_{n})}}$ is quasi-affine to the multiplication operator $M_{z^{(ms_{1},\cdot\cdot\cdot,ms_{n})}}$ on $H$. Furthermore, the reducing subspaces of $M_{z^{(ms_{1},\cdots,ms_{n})}}$ are characterized on $H$.


On Some Sums At The $A$-Points Of The $K$-Th Derivatives Of The Dirichlet $L$-Functions, Mohammed Mekkaoui, Abdallah Derbal, Kamel Mazhouda Jan 2020

On Some Sums At The $A$-Points Of The $K$-Th Derivatives Of The Dirichlet $L$-Functions, Mohammed Mekkaoui, Abdallah Derbal, Kamel Mazhouda

Turkish Journal of Mathematics

Let $L^{(k)}(s,\chi)$ be the $k$-th derivative of the Dirichlet L-function associated with a primitive character $\chi$ mod $q$ and $a$ be a complex number. The solutions of $L^{(k)}(s,\chi)=a$ are called $a$-points. In this paper, we give an asymptotic formula for the sums


Characterizations Of Dual Curves And Dual Focal Curves In Dual Lorentzian Space $ D^{3}_{1} $, Sareh Mehdizadeh Gilani, Nemat Abazari, Yusuf Yayli Jan 2020

Characterizations Of Dual Curves And Dual Focal Curves In Dual Lorentzian Space $ D^{3}_{1} $, Sareh Mehdizadeh Gilani, Nemat Abazari, Yusuf Yayli

Turkish Journal of Mathematics

In this paper, we have introduced dual Lorentzian connection, bracket and curvature tensor on dual Lorentzian space $ D_{1}^{3} .$ We have studied a dual curve in different situations in dual Lorentzian space $D^{3}_{1} $ and have found Bishop Darboux vector and some relations according to this vector field, Bishop frame and focal curve of the present dual curve. It has been shown that Bishop Darboux vector has a similar amount in three different cases of a dual curve and the first dual focal curvature of the aforementioned curve is constant function.


Linear Mappings Satisfying Some Recursive Sequences, Amin Hosseini, Mehdi Mohammadzadeh Karizaki Jan 2020

Linear Mappings Satisfying Some Recursive Sequences, Amin Hosseini, Mehdi Mohammadzadeh Karizaki

Turkish Journal of Mathematics

Let $\mathcal{A}$ be a unital, complex normed $\ast$-algebra with the identity element $\textbf{e}$ such that the set of all algebraic elements of $\mathcal{A}$ is norm dense in the set of all self-adjoint elements of $\mathcal{A}$ and let $\{D_n\}_{n = 0}^{\infty}$ and $\{\Delta_n\}_{n = 0}^{\infty}$ be sequences of continuous linear mappings on $\mathcal{A}$ satisfying \[ \left\lbrace \begin{array}{c l} D_{n + 1}(p) = \sum_{k = 0}^{n}D_{n - k}(p)D_k(p),\\ \\ \Delta_{n + 1}(p) = \sum_{k = 0}^{n}\Delta_{n - k}(p)D_k(p), \end{array} \right. \] for all projections $p$ of $\mathcal{A}$ and all nonnegative integers $n$. Moreover, suppose that $D_0(p) = D_0(p)^2$ holds for all projections …


On Basicity Of The System Of Eigenfunctions Of One Discontinuous Spectral Problem For Second Order Differential Equation For Grand-Lebesgue Space, Yusuf Zeren, Miqdad Ismailov, Fati̇h Şi̇ri̇n Jan 2020

On Basicity Of The System Of Eigenfunctions Of One Discontinuous Spectral Problem For Second Order Differential Equation For Grand-Lebesgue Space, Yusuf Zeren, Miqdad Ismailov, Fati̇h Şi̇ri̇n

Turkish Journal of Mathematics

Basicity of the system of eigenfunctions of some\textbf{ }discontinuous spectral problem for a second order differential equation with spectral parameter in boundary condition for grand-Lebesgue space $L_{p)} (-1;1)$ is studied in this work. Since the space is nonseparable, a subspace suitable for the spectral problem is defined. The subspace $G_{p)} (-1;1)$ of $L_{p)} (-1;1)$ generated by shift operator is considered. Basicity of the system of eigenfunctions for the space $G_{p)} (-1;1)\oplus C$, $1


On The Dynamics Of Certain Higher-Order Scalar Difference Equation: Asymptotics, Oscillation, Stability, Pavel Nesterov Jan 2020

On The Dynamics Of Certain Higher-Order Scalar Difference Equation: Asymptotics, Oscillation, Stability, Pavel Nesterov

Turkish Journal of Mathematics

We construct the asymptotics for solutions of the higher-order scalar difference equation that is equivalent to the linear delay difference equation $\Delta y(n)=-g(n)y(n-k)$. We assume that the coefficient of this equation oscillates at the certain level and the oscillation amplitude decreases as $n\to\infty$. Both the ideas of the centre manifold theory and the averaging method are used to construct the asymptotic formulae. The obtained results are applied to the oscillation and stability problems for the solutions of the considered equation.


Various Results For Series Expansions Of The Error Functions With The Complex Variable And Some Of Their Implications, Hüseyi̇n Irmak Jan 2020

Various Results For Series Expansions Of The Error Functions With The Complex Variable And Some Of Their Implications, Hüseyi̇n Irmak

Turkish Journal of Mathematics

This scientific investigation deals with introducing certain basic information relating to the error functions in z-plane, establishing extensive relations between various series expansions of the complex error functions and presenting a number of their implications.


Existence Of Self-Similar Solutions To Smoluchowski's Coagulation Equation With Product Kernel, Tanfer Tanriverdi̇ Jan 2020

Existence Of Self-Similar Solutions To Smoluchowski's Coagulation Equation With Product Kernel, Tanfer Tanriverdi̇

Turkish Journal of Mathematics

We explore, by using formal analysis, the existence of mass conserving self-similar solutions for Smoluchowski's coagulation equation when kernel $K(x,y)=x^{\lambda} y^{\mu}+x^{\mu} y^{\lambda}$ with $0


Surface Pencil With A Common Adjoint Curve, Ergi̇n Bayram Jan 2020

Surface Pencil With A Common Adjoint Curve, Ergi̇n Bayram

Turkish Journal of Mathematics

In the present paper,we construct surfaces possessing an adjoint curve of a given space curve as an asymptotic curve, geodesic or line of curvature. We obtain conditions for ruled surfaces and developable ones. Finally, we present illustrative examples to show the validity of the present method.


Some Results On Top Generalized Local Cohomology Modules With Respect To A System Of Ideals, Nguyen Minh Tri Jan 2020

Some Results On Top Generalized Local Cohomology Modules With Respect To A System Of Ideals, Nguyen Minh Tri

Turkish Journal of Mathematics

Let $R$ be a commutative Noetherian ring and $\Phi$ be a system of ideals of $R.$ In this paper, we study the annihilators and the set of attached prime ideals of top generalized local cohomology modules with respect to a system of ideals.


An Algorithm To Check The Equality Of Total Domination Number And Double Of Domination Number In Graphs, Seli̇m Bahadir Jan 2020

An Algorithm To Check The Equality Of Total Domination Number And Double Of Domination Number In Graphs, Seli̇m Bahadir

Turkish Journal of Mathematics

In graph theory, domination number and its variants such as total domination number are studied by many authors. Let the domination number and the total domination number of a graph $G$ without isolated vertices be $\gamma(G)$ and $\gamma_t(G)$, respectively. Based on the inequality $\gamma_t(G) \leq 2\gamma(G)$, we investigate the graphs satisfying the upper bound, that is, graphs $G$ with $\gamma_t(G) = 2\gamma(G)$. In this paper, we present some new properties of such graphs and provide an algorithm which can determine whether $\gamma_t(G) = 2\gamma(G)$ or not for a family of graphs not covered by the previous results in the literature.


Benedicks And Donoho-Stark Type Theorems, Lotfi Kamoun, Raoudha Laffi Jan 2020

Benedicks And Donoho-Stark Type Theorems, Lotfi Kamoun, Raoudha Laffi

Turkish Journal of Mathematics

In this paper, we prove a Benedicks type theorem and a Donoho-Stark type theorem, for the generalized Fourier transform $\mathcal{F}_\alpha$ associated to some differential operators that we call Flensted-Jensen operators, in various spaces such $\mathrm{L}^1_\alpha(\mathbb{K})$, $\mathrm{L}^2_\alpha(\mathbb{K})$ and $\mathrm{L}^1_\alpha(\mathbb{K})\cap\mathrm{L}^2_\alpha(\mathbb{K})$, where $\mathbb{K}=\mathbb{R}_+\times\mathbb{R}$


The Generalized Inverses Of The Products Of Two Elements In A Ring, Kai Yan, Qingping Zeng Jan 2020

The Generalized Inverses Of The Products Of Two Elements In A Ring, Kai Yan, Qingping Zeng

Turkish Journal of Mathematics

In this paper, new extensions of Jacobson's lemma and Cline's formula for Drazin inverses, generalized Drazin inverses, and ($m,n$)-pseudo-inverses are given. As applications, we provide a formula for the powers of the products of two elements and establish connections between two B-Fredholm elements through the canonical map.


On Hausdorff-Young Inequalities In Generalized Lebesgue Spaces, Miqdad Ismailov Jan 2020

On Hausdorff-Young Inequalities In Generalized Lebesgue Spaces, Miqdad Ismailov

Turkish Journal of Mathematics

Lebesgue spaces with the variable rate of summability are considered in this work. Generalizations of Riesz and Paley theorems are proved in these spaces. The obtained results are applied, in particular, to a classical exponential system.


On $\Mathcal{X}$-Gorenstein Projective Dimensions And Precovers, Bin Yu Jan 2020

On $\Mathcal{X}$-Gorenstein Projective Dimensions And Precovers, Bin Yu

Turkish Journal of Mathematics

For a class of $R$-modules $\mathcal{X}$ containing all projective $R$-modules, the $\mathcal{X}$-Gorenstein projective $R$-modules vary from projective to Gorenstein projective $R$-modules. We characterize the rings over which the left global $\mathcal{X}$-Gorenstein projective dimensions are finite. If further $\mathcal{Y}$ contains all injective $R$-modules, we show the existence of a new left global Gorenstein dimension of $R$ with respect to $\mathcal{X}$ and $\mathcal{Y}$ satisfying proper conditions. As an application we characterize Ding-Chen rings by this new global Gorenstein dimension and show the existence of Ding-Chen rings with infinite global Gorenstein dimension. We also show the existence of $\mathcal{X}$-Gorenstein projective precovers for a …


A Note On Simple Trinomial Units In $U_{1}(\Mathbb{Z}C_{P})$, Necat Görentaş Jan 2020

A Note On Simple Trinomial Units In $U_{1}(\Mathbb{Z}C_{P})$, Necat Görentaş

Turkish Journal of Mathematics

In this paper, some new notions are defined about the unit group $U_{1}(\mathbb{Z}G)$ of a finite group G. Especially, notion of simple unit is defined by using the number of elements in its support and absolutely small coefficients of the unit. Units are classified as monomial, binomial, trinomial and k-nomial, level, unit with level $l$ and simple unit. We have shown triviality of monomial units and nonexistence of binomial units in the unit group $U_{1}(\mathbb{Z}G)$ of an arbitrary finite group G. Some basic results and examples are posed about simple units and simple trinomial units in $U_{1}(\mathbb{Z}C_{p})$of a cyclic group …


On The Autocentralizer Subgroups Of Finite $P$--Groups, Parisa Seifizadeh, Ali Gholamian, Amirali Farokhniaee, Mohammad Mehdi Nasrabadi Jan 2020

On The Autocentralizer Subgroups Of Finite $P$--Groups, Parisa Seifizadeh, Ali Gholamian, Amirali Farokhniaee, Mohammad Mehdi Nasrabadi

Turkish Journal of Mathematics

Let $G$ be a finite group and ${\rm Aut}(G)$ be the group of automorphisms of $G.$ Then, the autocentralizer of an automorphism $\alpha\in {\rm Aut}(G)$ in $G$ is defined as $C_{G}(\alpha)= \lbrace g \in G\vert \alpha(g)=g\rbrace.$ Let $Acent(G)=\lbrace C_{G}(\alpha)\vert \alpha \in {\rm Aut}(G) \rbrace.$ If $\vert Acent(G)\vert= n,$ then $G$ is an $n$--autocentralizer group. In this paper, we classify all $n$--autocentralizer abelian groups for $n=$ 6, 7 and 8. We also obtain a lower bound on the number of autocentralizer subgroups for $p$--groups, where $p$ is a prime number. We show that if $p\neq 2,$ there is no $n$--autocentralizer $p$--group …


On The Chromatic Polynomial And The Domination Number Of $K$-Fibonacci Cubes, Ömer Eğeci̇oğlu, Eli̇f Saygi, Zülfükar Saygi Jan 2020

On The Chromatic Polynomial And The Domination Number Of $K$-Fibonacci Cubes, Ömer Eğeci̇oğlu, Eli̇f Saygi, Zülfükar Saygi

Turkish Journal of Mathematics

Fibonacci cubes are defined as subgraphs of hypercubes, where the vertices are those without two consecutive 1's in their binary string representation. $k$-Fibonacci cubes are in turn special subgraphs of Fibonacci cubes obtained by eliminating certain edges. This elimination is carried out at the step analogous to where the fundamental recursion is used to construct Fibonacci cubes themselves from the two previous cubes by link edges. In this work, we calculate the vertex chromatic polynomial of $k$-Fibonacci cubes for $k=1,2$. We also determine the domination number and the total domination number of $k$-Fibonacci cubes for $n,k \leq 12$ by using …


Existence Results Of Positive Solutions For Kirchhoff Type Biharmonic Equation Via Bifurcation Methods*, Jinxiang Wang, Dabin Wang Jan 2020

Existence Results Of Positive Solutions For Kirchhoff Type Biharmonic Equation Via Bifurcation Methods*, Jinxiang Wang, Dabin Wang

Turkish Journal of Mathematics

This paper is concerned with the existence of positive solutions for the fourth order Kirchhoff type problem $$ \left\{\begin{array}{ll} \Delta^{2}u-(a+b\int_\Omega \nabla u ^2dx)\triangle u=\lambda f(u(x)),\ \ \text{in}\ \Omega,\\ u=\triangle u=0,\ \ \text{on}\ \partial\Omega,\\ \end{array} \right. $$ where $\Omega\subset \mathbb{R}^{N}$($N\geq 1$) is a bounded domain with smooth boundary $\partial \Omega$, $a>0, b\geq 0$ are constants, $\lambda\in \mathbb{R}$ is a parameter. For the case $f(u)\equiv u$, we use an argument based on the linear eigenvalue problems of fourth order elliptic equations to show that there exists a unique positive solution for all $\lambda>\Lambda_{1,a}$, here $\Lambda_{1,a}$ is the first eigenvalue of …


Application Of Spectral Mapping Method To Dirac Operator, Rauf Ami̇rov, Merve Arslantaş Jan 2020

Application Of Spectral Mapping Method To Dirac Operator, Rauf Ami̇rov, Merve Arslantaş

Turkish Journal of Mathematics

In the present study, theorems related to the uniqueness of the solution of inverse problems for Dirac equations system are proved by applying spectral mapping method. With the help of this method, the inverse problem is reduced to the so-called main equation, which corresponds to the problem of existence and uniqueness of the solution of the system of linear equations in the Banach space.


Dynamics Of A Fluid Equation With Neumann Boundary Conditions, Limin Chen, Shengjun Li, Yumei Zou Jan 2020

Dynamics Of A Fluid Equation With Neumann Boundary Conditions, Limin Chen, Shengjun Li, Yumei Zou

Turkish Journal of Mathematics

We study the dynamics of a Neumann boundary value problem arising in fluid dynamics. We prove the nonexistence, existence and uniqueness of positive solutions under suitable conditions. At the same time, under stricter conditions, we also obtain the dynamic properties of the Neumann boundary value problem, such as the stability and instability of positive solutions. The methods of proof mainly involve the upper and lower solutions method, eigenvalue theory and some analysis techniques.


Hypergeometric Distribution Of The Number Of Draws From An Urn With Two Types Of Items Before One Of The Counts Reaches A Threshold, J. L. Gonzalez-Santander Jan 2020

Hypergeometric Distribution Of The Number Of Draws From An Urn With Two Types Of Items Before One Of The Counts Reaches A Threshold, J. L. Gonzalez-Santander

Turkish Journal of Mathematics

We consider an urn with $R$ elements of one type and $B$ elements of other type. We calculate the probability distribution $P_{n_{R},n_{B}}^{R,B}\left( s\right) $ wherein the random variable $s$ is the number of draws from the urn until we reach $n_{R}$ elements of type $R$ or $n_{B}$ elements of type $B$. We calculate the mean value $\left\langle s\right\rangle $ and the standard deviation $\sigma $ of $P_{n_{R},n_{B}}^{R,B}\left( s\right) $ in terms of hypergeometric functions. For $n_{R}=n_{B}$ and $B=R$ , we reduce $\left\langle s\right\rangle $ and $\sigma $ in terms of elementary functions. Also, the normalization condition leads to a new …


Classification Of Some Subclasses Of 6-Dimensional Nilpotent Leibniz Algebras, Ismail Demir Jan 2020

Classification Of Some Subclasses Of 6-Dimensional Nilpotent Leibniz Algebras, Ismail Demir

Turkish Journal of Mathematics

This article is a contribution to the improvement of classification theory in Leibniz algebras. We extend the method of congruence classes of matrices of bilinear forms that was used to classify complex nilpotent Leibniz algebras with one dimensional derived algebra. In this work we focus on applying this method to the classification of 6-dimensional complex nilpotent Leibniz algebras with two dimensional derived algebra.


A Unique Solution To A Fourth-Order Three-Point Boundary Value Problem, Vedat Suat Ertürk Jan 2020

A Unique Solution To A Fourth-Order Three-Point Boundary Value Problem, Vedat Suat Ertürk

Turkish Journal of Mathematics

In this study, it is aimed to examine the solutions of the following nonlocal boundary value problem \begin{equation*} y^{(4)}+g(x,y)=0,x\in [{c,d}], y(c)=y'(c)=y''(c)=0,y(d)=\lambda y(\xi). \end{equation*} Here, $\xi\in ({c,d}),\lambda \in \mathbb{R},g\in C([{c,d}]\times \mathbb{R},\mathbb{R})$ and $g(x,0)\neq 0.$ It is concentrated on applications of Green's function that corresponds to the above problem to derive existence and uniqueness results for the solutions. One example is also given to demonstrate the results.


The Third Logarithmic Coefficient For The Class $\Mathcal{S}$, Milutin Obradovic, Nikola Tuneski Jan 2020

The Third Logarithmic Coefficient For The Class $\Mathcal{S}$, Milutin Obradovic, Nikola Tuneski

Turkish Journal of Mathematics

In this paper we give an upper bound of the third logarithmic coefficient for the class $\mathcal{S}$ of univalent functions in the unit disc.