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Modification Of The Sector Theorem Of Kondo-Tanaka, Eric Choi
Modification Of The Sector Theorem Of Kondo-Tanaka, Eric Choi
Turkish Journal of Mathematics
Kondo-Tanaka proved that if a rotationally symmetric plane $M_m$ is von Mangoldt or Cartan-Hadamard outside a compact set and has finite total curvature, then it has a sector with no pair of cut points. We show that the condition of finite total curvature can be removed. %The abstract should provide clear information about the research and the results obtained, and should not exceed 200 words. The abstract should not contain citations.
On Positive Periodic Solutions To Third-Order Integro-Differential Equations With Distributed Delays, Mimia Benhadri, Tomas Caraballo
On Positive Periodic Solutions To Third-Order Integro-Differential Equations With Distributed Delays, Mimia Benhadri, Tomas Caraballo
Turkish Journal of Mathematics
In this paper, we investigate the existence of positive periodic solutions of a third-order nonlinear integro-differential equation with distributed delays, by using the Green function and the Krasnosel'skii fixed point theorem in cones of Banach spaces, providing new results on this field. Three examples are analyzed to illustrate the effectiveness of the abstract results.
Identities Involving Special Functions From Hypergeometric Solution Of Algebraic Equations, Juan Luis Gonzalez-Santander
Identities Involving Special Functions From Hypergeometric Solution Of Algebraic Equations, Juan Luis Gonzalez-Santander
Turkish Journal of Mathematics
From the algebraic solution of $x^{m}-x+t=0$ for $m=2,3,4$ and the corresponding solution in terms of hypergeometric functions, we obtain a set of reduction formulas for hypergeometric functions. By differentiation and integration of these results, and applying other known reduction formulas of hypergeometric functions, we derive new reduction formulas of special functions as well as the calculation of some definite integrals in terms of elementary functions.
Fractional Semilinear Neumann Problem With Critical Nonlinearity, Zhenfeng Jin, Hongrui Sun
Fractional Semilinear Neumann Problem With Critical Nonlinearity, Zhenfeng Jin, Hongrui Sun
Turkish Journal of Mathematics
In this paper, we consider the following critical fractional semilinear Neumann problem \begin{equation*} \begin{cases} (-\Delta)^{1/2}u+\lambda u=u^{\frac{n+1}{n-1}},~u>0\quad&\, \mathrm{in}\ \Omega,\\ \partial_\nu{u}=0 &\mathrm{on}\ \partial\Omega, \end{cases} \end{equation*} where $\Omega\subset\mathbb{R}^n~(n\geq5)$ is a smooth bounded domain, $\lambda>0$ and $\nu$ is the outward unit normal to $\partial\Omega$. We prove that there exists a constant $\lambda_0>0$ such that the above problem admits a minimal energy solution for $\lambda<\lambda_0$. Moreover, if $\Omega$ is convex, we show that this solution is constant for sufficiently small $\lambda$.
Liouville-Type Theorem For One-Dimensional Porous Medium Systems With Sources, Anh Tuan Duong
Liouville-Type Theorem For One-Dimensional Porous Medium Systems With Sources, Anh Tuan Duong
Turkish Journal of Mathematics
In this paper, we are concerned with the one-dimensional porous medium system with sources \begin{align*} \begin{cases}u_t-( u^m)_{xx} =a_{11}u^{p}+a_{12} u^rv^{r+m}, (x,t)\in J\times I\subset\mathbb{R}\times \mathbb{R}\\ v_t-(v^m)_{xx} =a_{21} u^{r+m}v^{r}+a_{22}v^{p},\;(x,t)\in J\times I\subset \mathbb{R}\times \mathbb{R}, \end{cases} \end{align*} where $p=2r+m$, $m>1$, $r>0$. Under the conditions $a_{12}\geq 0, a_{21}\geq 0$, $a_{11}>0$, and $a_{22}>0$, we prove that the system does not possess any nontrivial nonnegative weak solution.
A Short Note On A New Approach To Rayleigh-Bénard-Chandrasekhar Convection In Weakly Electrically Conducting Viscoelastic Liquids, Hati̇ce Muti̇
A Short Note On A New Approach To Rayleigh-Bénard-Chandrasekhar Convection In Weakly Electrically Conducting Viscoelastic Liquids, Hati̇ce Muti̇
Turkish Journal of Mathematics
The onset of magnetoconvection (known as Rayleigh-Bénard-Chandrasekhar convection) in two relaxation time viscoelastic liquids is studied here without seeking explicit recourse to a normal stress formulation as is usually done in these studies. Magnetoconvection refers to the flow of fluid in the presence of both thermal gradients (Rayleigh-Bénard convection) and a magnetic field. When these two effects are combined, they can lead to interesting and complex patterns of fluid motion. Understanding magnetoconvection in viscoelastic liquids is crucial for various industrial and scientific applications. The hyperbolic-type of linear momentum equation is decomposed into two first-order equations in time by cleverly separating …
On The Weak And Strong Solutions Of The Velocity-Vorticity Model Of The $G$-Navier-Stokes Equations, Özge Kazar, Meryem Kaya
On The Weak And Strong Solutions Of The Velocity-Vorticity Model Of The $G$-Navier-Stokes Equations, Özge Kazar, Meryem Kaya
Turkish Journal of Mathematics
In this work, we consider a velocity-vorticity formulation for the $g$-Navier-Stokes equations. The system is constructed by combining the velocity-pressure system which is included by using the rotational formulation of the nonlinearity and the vorticity equation for the $g$ -Navier-Stokes equations. We prove the existence and uniqueness of weak and strong solutions of this system with the periodic boundary conditions.
Existence Results For Impulsive Dynamic Singular Nonlinear Sturm-Liouville Equations On Infinite Intervals, Bi̇lender Paşaoğlu Allahverdi̇ev, Hüseyi̇n Tuna, Hamlet Abdullaoğlu Isayev
Existence Results For Impulsive Dynamic Singular Nonlinear Sturm-Liouville Equations On Infinite Intervals, Bi̇lender Paşaoğlu Allahverdi̇ev, Hüseyi̇n Tuna, Hamlet Abdullaoğlu Isayev
Turkish Journal of Mathematics
The purpose of this study is to investigate an impulsive dynamic singular nonlinear Sturm-Liouville problem on infinite intervals. The existence and uniqueness of the solutions of such problem will be investigated by considering Weyl's limit-circle case.
Pell-Lucas Collocation Method For Solving A Class Of Second Order Nonlinear Differential Equations With Variable Delays, Şuayi̇p Yüzbaşi, Gamze Yildirim
Pell-Lucas Collocation Method For Solving A Class Of Second Order Nonlinear Differential Equations With Variable Delays, Şuayi̇p Yüzbaşi, Gamze Yildirim
Turkish Journal of Mathematics
In this study, the approximate solution of the nonlinear differential equation with variable delays is investigated by means of a collocation method based on the truncated Pell-Lucas series. In the first stage of the method, the assumed solution form (the truncated Pell-Lucas polynomial solution) is expressed in the matrix form of the standard bases. Next, the matrix forms of the necessary derivatives, the nonlinear terms, and the initial conditions are written. Then, with the help of the equally spaced collocation points and these matrix relations, the problem is reduced to a system of nonlinear algebraic equations. Finally, the obtained system …
An Invariant Of Regular Isotopy For Disoriented Links, İsmet Altintaş, Hati̇ce Parlatici
An Invariant Of Regular Isotopy For Disoriented Links, İsmet Altintaş, Hati̇ce Parlatici
Turkish Journal of Mathematics
In this paper, we define a two-variable polynomial invariant of regular isotopy, $M_{K}$ for a disoriented link diagram $K$. By normalizing the polynomial $M_{K}$ using complete writhe, we obtain a polynomial invariant of ambient isotopy, $N_{K}$, for a disoriented link diagram $K$. The polynomial $N_{K}$ is a generalization of the expanded Jones polynomial for disoriented links and is an expansion of the Kauffman polynomial $F$ to the disoriented links. Moreover, the polynomial $M_{K}$ is an expansion of the Kauffman polynomial $L$ to the disoriented links.
Bipolar Soft Ideal Rough Set With Applications In Covid-19, Heba I. Mustafa
Bipolar Soft Ideal Rough Set With Applications In Covid-19, Heba I. Mustafa
Turkish Journal of Mathematics
Bipolar soft rough set represents an important mathematical model to deal with uncertainty. This theory represents a link between bipolar soft set and rough set theories. This study introduced the concept of topological bipolar soft set by combining a bipolar soft set with topologies. Also, the topological structure of bipolar soft rough set has been discussed by defining the bipolar soft rough topology. The main objective of this paper is to present some solutions to develop and modify the approach of the bipolar soft rough sets. Two kinds of bipolar soft ideal approximation operators which represent extensions of bipolar soft …
A New Approach To Matrix Isomorphisms Of Complex Clifford Algebras Via Cantor Set, Derya Çeli̇k
A New Approach To Matrix Isomorphisms Of Complex Clifford Algebras Via Cantor Set, Derya Çeli̇k
Turkish Journal of Mathematics
We give a new way to obtain the standard isomorphisms of complex Clifford algebras, known as the tensor product of Pauli matrices, by representing the complex Clifford algebras on the space of complex valued functions defined over a finite subset of the Cantor set.
Forming Coupled Dispersionless Equations Of Families Of Bertrand Curves, Kemal Eren
Forming Coupled Dispersionless Equations Of Families Of Bertrand Curves, Kemal Eren
Turkish Journal of Mathematics
In this study, we establish a link of the coupled dispersionless (CD) equations system with the motion of Bertrand curve pairs. Moreover, we find the Lax equations that provide the integrability of these equations. By taking an appropriate choice of variables we show the link of the short pulse (SP) equation with the motion of Bertrand curve pairs via the reciprocal (hodograph) transformation. Finally, we prove that the conserved quantity of the corresponding coupled dispersionless equations obtained from each of these curve pairs is constant.
On The Distribution Of Adjacent Zeros Of Solutions To First-Order Neutral Differential Equations, Emad R. Attia, Ohoud N. Al-Masarer, Irena Jadlovska
On The Distribution Of Adjacent Zeros Of Solutions To First-Order Neutral Differential Equations, Emad R. Attia, Ohoud N. Al-Masarer, Irena Jadlovska
Turkish Journal of Mathematics
The purpose of this paper is to study the distribution of zeros of solutions to a first-order neutral differential equation of the form \begin{equation*} \left[x(t) + p(t) x(t-\tau)\right]' + q(t) x(t-\sigma) = 0, \quad t \geq t_0, \end{equation*} where $p\in C([t_0,\infty),[0,\infty))$, $q \in C([t_0,\infty),(0,\infty))$, $\tau,\sigma>0$, and $\sigma>\tau$. We obtain new upper bound estimates for the distance between consecutive zeros of solutions, which improve upon many of the previously known ones. The results are formulated so that they can be generalized without much effort to equations for which the distribution of zeros problem is related to the study of …
Novel Correlation Coefficients For Interval-Valued Fermatean Hesitant Fuzzy Sets With Pattern Recognition Application, İbrahi̇m Demi̇r
Novel Correlation Coefficients For Interval-Valued Fermatean Hesitant Fuzzy Sets With Pattern Recognition Application, İbrahi̇m Demi̇r
Turkish Journal of Mathematics
A combination of interval-valued Fermatean fuzzy sets with Fermatean hesitant fuzzy elements in the form of interval values is known as an interval-valued Fermatean hesitant fuzzy set. Since Fermatean hesitant fuzzy sets are effective instruments for representing more complex, ambiguous, and hazy information, interval-valued Fermatean hesitant fuzzy sets are expansions of these sets. This investigation will concentrate on four different types of correlation coefficients for Fermatean hesitant fuzzy sets and expand them to include correlation coefficients and weighted correlation coefficients for interval-valued Fermatean hesitant fuzzy sets. Finally, the numerical examples demonstrate the viability and usefulness of the suggested methodologies in …
Geodesics And Isocline Distributions In Tangent Bundles Of Nonflat Lorentzian-Heisenberg Spaces, Murat Altunbaş
Geodesics And Isocline Distributions In Tangent Bundles Of Nonflat Lorentzian-Heisenberg Spaces, Murat Altunbaş
Turkish Journal of Mathematics
Let $(H_{3},g_{1})$ and $(H_{3},g_{2})$ be the Lorentzian-Heisenberg spaces with nonflat metrics $g_{1}$ and $g_{2},\ $and $(TH_{3},g_{1}^{s}),\ (TH_{3},g_{2}^{s})$ be their tangent bundles with the Sasaki metric, respectively. In the present paper, we find nontotally geodesic distributions in tangent bundles by using lifts of contact forms from the base manifold $H_{3}.$We give examples for totally geodesic but not isocline distributions. We study the geodesics of tangent bundles by considering horizontal and natural lifts of geodesics of the base manifold $H_{3}$. We also investigate more general classes of geodesics which are not obtained from horizontal and natural lifts of geodesics.
On The Band Functions And Bloch Functions, Oktay Veli̇ev
On The Band Functions And Bloch Functions, Oktay Veli̇ev
Turkish Journal of Mathematics
In this paper, we consider the continuity of the band functions and Bloch functions of the differential operators generated by the differential expressions with periodic matrix coefficients.
A Note On "Some Properties Of Second-Order Weak Subdifferentials" [Turkish Journal Of Mathematics (2021)45: 955-960], Qilin Wang, Min Liu
A Note On "Some Properties Of Second-Order Weak Subdifferentials" [Turkish Journal Of Mathematics (2021)45: 955-960], Qilin Wang, Min Liu
Turkish Journal of Mathematics
In this note, we provide an example to illustrate that Proposition 2.4 in [Turkish Journal of Mathematics (2021)45: 955-960)] is incorrect, and give a modification of the proposition. Two examples are provided to illustrate the modified result. Meanwhile, we establish a convex function, and correct the proof of Theorem 2.3 in [Turkish Journal of Mathematics (2021)45: 955-960)] by the function.
Geometric Singularities And Regularity Of Solution Of The Stokes System In Nonsmooth Domains, Yasir Nadeem Anjam
Geometric Singularities And Regularity Of Solution Of The Stokes System In Nonsmooth Domains, Yasir Nadeem Anjam
Turkish Journal of Mathematics
This paper deals with the geometrical singularities of the weak solution of the mixed boundary value problem governed by the stationary Stokes system in two-dimensional nonsmooth domains with corner points and points at which the type of boundary conditions changes. The presence of these points on the boundary generally generates local singularities in the solution. We will see the impact of the geometrical singularities of the boundary or the mixed boundary conditions on the qualitative properties of the solution including its regularity. Moreover, the asymptotic singular representations for the solution which inherently depend on the zeros of certain transcendental functions …
Separation, Connectedness, And Disconnectedness, Mehmet Baran
Separation, Connectedness, And Disconnectedness, Mehmet Baran
Turkish Journal of Mathematics
The aim of this paper is to introduce the notions of hereditarily disconnected and totally disconnected objects in a topological category and examine the relationship as well as interrelationships between them. Moreover, we characterize each of $T_{2}$, connected, hereditarily disconnected, and totally disconnected objects in some topological categories and compare our results with the ones in the category of topological spaces.
The Class Of Demi Kb-Operators On Banach Lattices, Hedi Benkhaled, Aref Jeribi
The Class Of Demi Kb-Operators On Banach Lattices, Hedi Benkhaled, Aref Jeribi
Turkish Journal of Mathematics
In this paper, we introduce and study the new concept of demi KB-operators. Let $E$ be a Banach lattice. An operator $T: E\longrightarrow E$ is said to be a demi KB-operator if, for every positive increasing sequence $\{x_{n}\}$ in the closed unit ball $\mathcal{B}_{E}$ of $E$ such that $\{x_{n}-Tx_{n}\}$ is norm convergent to $x\in E$, there is a norm convergent subsequence of $\{x_{n}\}$. If the latter sequence has a weakly convergent subsequence then $T$ is called a weak demi KB-operator. We also investigate the relationship of these classes of operators with classical notions of operators, such as b-weakly demicompact operators …
Approximation Results For The Moments Of Random Walk With Normally Distributed Interference Of Chance, Zülfi̇ye Hanali̇oğlu, Aynura Poladova, Tahi̇r Khani̇yev
Approximation Results For The Moments Of Random Walk With Normally Distributed Interference Of Chance, Zülfi̇ye Hanali̇oğlu, Aynura Poladova, Tahi̇r Khani̇yev
Turkish Journal of Mathematics
In this study, a random walk process $\left(X\left(t\right)\right)$ with normally distributed interference of chance is considered. In the literature, this process has been shown to be ergodic and the limit form of the ergodic distribution has been found. Here, unlike previous studies, the moments of the $X\left(t\right)$ process are investigated. Although studies investigating the moment problem for various stochastic processes (such as renewal-reward processes) exist in the literature, it has not been considered for random walk processes, as it requires the use of new mathematical tools. Therefore, in this study, firstly, the exact formulas for the first four moments of …
Inverse Nodal Problem For The Quadratic Pencil Of The Sturm$-$Liouville Equations With Parameter-Dependent Nonlocal Boundary Condition, Yaşar Çakmak, Baki̇ Keski̇n
Inverse Nodal Problem For The Quadratic Pencil Of The Sturm$-$Liouville Equations With Parameter-Dependent Nonlocal Boundary Condition, Yaşar Çakmak, Baki̇ Keski̇n
Turkish Journal of Mathematics
In this paper, we consider the inverse nodal problem for a quadratic pencil of the Sturm$-$Liouville equations with parameter-dependent Bitsadze$-$Samarskii type nonlocal boundary condition and we give an algorithm for the reconstruction of the potential functions by obtaining the asymptotics of the nodal points.
Generalized Elliptical Quaternions With Some Applications, Harun Bariş Çolakoğlu, Mustafa Özdemi̇r
Generalized Elliptical Quaternions With Some Applications, Harun Bariş Çolakoğlu, Mustafa Özdemi̇r
Turkish Journal of Mathematics
In this article, quaternions, which is a preferred and elegant method for expressing spherical rotations, are generalized with the help of generalized scalar product spaces, and elliptical rotations on any given ellipsoid are examined by them. To this end, firstly, we define the generalized elliptical scalar product space which accepts the given ellipsoid as a sphere and determines skew symmetric matrices, and the generalized vector product related to this scalar product space. Then we define the generalized elliptical quaternions by using these notions. Finally, elliptical rotations on any ellipsoid in the space are examined by using the unit generalized elliptical …
Studying A Doubly Nonlinear Model Of Slightly Compressible Forchheimer Flows In Rotating Porous Media, Emi̇ne Çeli̇k, Luan Hoang, Thinh Kieu
Studying A Doubly Nonlinear Model Of Slightly Compressible Forchheimer Flows In Rotating Porous Media, Emi̇ne Çeli̇k, Luan Hoang, Thinh Kieu
Turkish Journal of Mathematics
We study the generalized Forchheimer flows of slightly compressible fluids in rotating porous media. In the problem's model, the varying density in the Coriolis force is fully accounted for without any simplifications. It results in a doubly nonlinear parabolic equation for the density. We derive a priori estimates for the solutions in terms of the initial, boundary data and physical parameters, emphasizing on the case of unbounded data. Weighted Poincare-Sobolev inequalities suitable to the equation's nonlinearity, adapted Moser's iteration, and maximum principle are used and combined to obtain different types of estimates.
Attractors For Semigroups With Multi-Dimensional Time And Pdes In Unbounded Domains, Anna Kostianko, Sergey Zelik
Attractors For Semigroups With Multi-Dimensional Time And Pdes In Unbounded Domains, Anna Kostianko, Sergey Zelik
Turkish Journal of Mathematics
We develop the attractors theory for the semigroups with multidimensional time belonging to some closed cone in an Euclidean space and apply the obtained general results to partial differential equations (PDEs) in unbounded domains. The main attention is payed to elliptic boundary problems in general unbounded domains. In contrast to the previous works in this direction our theory does not require the underlying domain to be cylindrical or cone-like or to be shift semiinvariant with respect to some direction. In particular, the theory is applicable to the exterior domains.
Discontinuous Galerkin Method For Blow-Up Solutions Of Nonlinear Wave Equations, Asma Azaiez, Mondher Benjemaa, Aida Jrajria, Hatem Zaag
Discontinuous Galerkin Method For Blow-Up Solutions Of Nonlinear Wave Equations, Asma Azaiez, Mondher Benjemaa, Aida Jrajria, Hatem Zaag
Turkish Journal of Mathematics
e develop and study an explicit time-space discrete discontinuous Galerkin finite element method to approximate the solution of one-dimensional nonlinear wave equations. We show that the numerical scheme is stable if a nonuniform time mesh is considered. We also investigate the blow-up phenomena and we prove that under weak convergence assumptions, the numerical blow-up time tends toward the theoretical one. The validity of our results is confirmed throughout several examples and benchmarks.