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Full-Text Articles in Physical Sciences and Mathematics

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.


On Tetravalent Normal Edge-Transitive Cayley Graphs On The Modular Group, Hesam Sharifi, Mohammad Reza Darafsheh Jan 2017

On Tetravalent Normal Edge-Transitive Cayley Graphs On The Modular Group, Hesam Sharifi, Mohammad Reza Darafsheh

Turkish Journal of Mathematics

A Cayley graph $\Gamma=Cay(G, S)$ on a group $G$ with respective toa subset $S\subseteq G$, $S=S^{-1}, 1\notın S$, is said to be normaledge-transitive if $N_{\mathbb{A}ut(\Gamma)}(\rho(G))$ is transitiveon edges of $\Gamma$, where $\rho(G)$ is a subgroup of $\mathbb{A}ut(\Gamma)$isomorphic to $G$. We determine all connected tetravalent normaledge-transitive Cayley graphs on the modular group of order $8n$in the case that every element of $S$ is of order $4n$.


Cyclic Codes Over $\Mathbb{Z}_{4}+U\Mathbb{Z}_{4}+U^{2}\Mathbb{Z}_{4}$, Mehmet Özen, Nazmi̇ye Tuğba Özzai̇m, Nuh Aydin Jan 2017

Cyclic Codes Over $\Mathbb{Z}_{4}+U\Mathbb{Z}_{4}+U^{2}\Mathbb{Z}_{4}$, Mehmet Özen, Nazmi̇ye Tuğba Özzai̇m, Nuh Aydin

Turkish Journal of Mathematics

In this paper, we study cyclic codes over the ring $R=\mathbb{Z}_{4}+u\mathbb{Z}_{4}+u^{2}\mathbb{Z}_{4}$,where $u^{3}=0$. We investigate Galois extensions of this ring and the ideal structure of these extensions.The results are then used to obtain facts about cyclic codes over $R$. We also determine the general form of the generator of a cyclic code and find its minimal spanning sets. Finally, we obtain many new linear codes over $\mathbb{Z}_4$ by considering Gray images of cyclic codes over $R$.


Chaos-Related Properties On The Product Of Semiflows, Alica Miller, Chad Money Jan 2017

Chaos-Related Properties On The Product Of Semiflows, Alica Miller, Chad Money

Turkish Journal of Mathematics

In this paper we generalize some results about the chaos-related properties on the product of two semiflows, which appeared in the lite\-rature in the last few years, to the case of the most general possible acting monoids. In order to do that we introduce some new notions, namely the notions of a directional, psp and sip monoid, and the notion of a strongly transitive semiflow. In particular, we obtain a sufficient condition for the Devaney chaoticity of a product, which works for the (very large) class of the psp acting monoids.


On Subdirectly Irreducible Regular Bands, Zheng-Pan Wang, Jing Leng, Hou-Yi Yu Jan 2017

On Subdirectly Irreducible Regular Bands, Zheng-Pan Wang, Jing Leng, Hou-Yi Yu

Turkish Journal of Mathematics

Subdirectly irreducible regular bands whose structural semilattices are finite chains are characterized in terms of arefined semilattice of semigroups.


Sufficient Conditions For The Compactifiability Of A Closed One-Form Foliation, Irina Gelbukh Jan 2017

Sufficient Conditions For The Compactifiability Of A Closed One-Form Foliation, Irina Gelbukh

Turkish Journal of Mathematics

We study the foliation defined by a closed $1$-form on a connected smooth closed orientable manifold.We call such a foliation compactifiable if all its leaves are closed in the complement of the singular set.In this paper, we give sufficient conditions for compactifiability of the foliation in homological terms.We also show that under these conditions, the foliation can be defined by closed $1$-forms with the ranks of their groups of periods in a certain range.In addition, we describe the structure of the group generated by the homology classes of all compact leaves of the foliation.


The Hahn-Banach Theorem For $A$-Linear Operators, Bahri̇ Turan, Fatma Bi̇li̇ci̇ Jan 2017

The Hahn-Banach Theorem For $A$-Linear Operators, Bahri̇ Turan, Fatma Bi̇li̇ci̇

Turkish Journal of Mathematics

In this short paper we present a generalization of the Hahn--Banach extensiontheorem for $A$-linear operators. Some theoretical applications andresults are given.


Tetravalent Normal Edge-Transitive Cayley Graphs On A Certain Group Of Order $6n$, Mohammad Reza Darafsheh, Maysam Yaghoobian Jan 2017

Tetravalent Normal Edge-Transitive Cayley Graphs On A Certain Group Of Order $6n$, Mohammad Reza Darafsheh, Maysam Yaghoobian

Turkish Journal of Mathematics

Let $U_{6n}= \langle a,b a^{2n}=b^{3}=1,a^{-1}ba=b^{-1}\rangle $ be a groupof order 6n. In this paper tetravalent normal edge-transitive Cayleygraphs on $U_{6n}$ are considered. In this way several nonequivalent normaledge-transitive Cayley graphs on $U_{6n}$ are obtained whose automorphismgroups are given exactly.


Warped Product Spaces With Ricci Conditions, Sang Deok Lee, Byung Hak Kim, Jin Hyuk Choi Jan 2017

Warped Product Spaces With Ricci Conditions, Sang Deok Lee, Byung Hak Kim, Jin Hyuk Choi

Turkish Journal of Mathematics

In this paper, we study the Ricci soliton in the Riemannian products$M=R^n \times B$ and warped products $M=R \times _f B$ of theEuclidean space and Riemannian manifolds, and the gradient Riccisoliton in the warped products $M=S^1 \times _f B$ of 1-dimensionalcircle and Riemannian manifolds. Moreover, we introduce the concept ofthe generalized Ricci soliton and we suggest the method of constructionof the Riemannian manifold $(M, g)$ with a Ricci soliton $g$.Finally, we also study the Lorentzian warped products with the Riccisoliton.


On The Rate Of $L_P$-Convergence Of Balakrishnan—Rubin-Type Hypersingular Integrals Associated To The Gauss-Weierstrass Semigroup, Meli̇h Eryi̇ği̇t, Seli̇m Çobanoğlu Jan 2017

On The Rate Of $L_P$-Convergence Of Balakrishnan—Rubin-Type Hypersingular Integrals Associated To The Gauss-Weierstrass Semigroup, Meli̇h Eryi̇ği̇t, Seli̇m Çobanoğlu

Turkish Journal of Mathematics

We introduce a family of Balakrishnan—Rubin-type hypersingular integrals depending ona parameter $\varepsilon$ and generated by the Gauss—Weierstrass semigroup. Then the connection between the order of $L_p$—smoothness of a $L_p$—function $\varphi$and the rate of $L_p$-convergence of these families to $\varphi$, as $\varepsilon$ tends to 0, is obtained.


Braided Regular Crossed Modules Bifibered Over Regular Groupoids, Alper Odabaş, Erdal Ulualan Jan 2017

Braided Regular Crossed Modules Bifibered Over Regular Groupoids, Alper Odabaş, Erdal Ulualan

Turkish Journal of Mathematics

We show that the forgetful functor from the category ofbraided regular crossed modules to the category of regular (or whiskered) groupoids is a fibration and also a cofibration.


Minimizing Graph Of The Connected Graphs Whose Complements Are Bicyclic With Two Cycles, Muhammad Javaid Jan 2017

Minimizing Graph Of The Connected Graphs Whose Complements Are Bicyclic With Two Cycles, Muhammad Javaid

Turkish Journal of Mathematics

In a certain class of graphs, a graph is called minimizing if the least eigenvalueof its adjacency matrix attains the minimum. A connected graph containing two or three cycles is called a bicyclic graph if its number of edges is equal to its number of vertices plus one. In this paper, we characterize the minimizinggraph among all the connected graphs that belong to a class of graphs whose complements are bicyclic with two cycles.


Corrigendum: On Density Theorems For Rings Of Krull Type With Zero Divisors, Başak Ay Saylam Jan 2017

Corrigendum: On Density Theorems For Rings Of Krull Type With Zero Divisors, Başak Ay Saylam

Turkish Journal of Mathematics

This corrigendum is written to correct some parts of the paper "On density theorems for rings of Krull type with zero divisors". The proofs of Proposition 2.4 and Proposition 4.3 are incorrect and the current note makes the appropriate corrections.


Arf Numerical Semigroups, Sedat İlhan, Hali̇l İbrahi̇m Karakaş Jan 2017

Arf Numerical Semigroups, Sedat İlhan, Hali̇l İbrahi̇m Karakaş

Turkish Journal of Mathematics

The aim of this work is to exhibit the relationship between the Arf closure of a numerical semigroup$S$ and its Lipman semigroup $L(S).$ This relationship is then used to give direct proofs of some characterizations of Arf numerical semigroups through their Lipman sequences of semigroups. We also give an algorithmic construction of the Arf closure of a numerical semigroup via its Lipman sequence of semigroups.


A Note On The Conjugacy Problem For Finite Sylow Subgroups Of Linear Pseudofinite Groups, Pinar Uğurlu Kowalski̇ Jan 2017

A Note On The Conjugacy Problem For Finite Sylow Subgroups Of Linear Pseudofinite Groups, Pinar Uğurlu Kowalski̇

Turkish Journal of Mathematics

We prove the conjugacy of Sylow $2$-subgroups in pseudofinite $\mathfrak{M}_c$ (in particular linear) groups under the assumption that there is at least one finite Sylow $2$-subgroup. We observe the importance of the pseudofiniteness assumption by analyzing an example of a linear group with nonconjugate finite Sylow $2$-subgroups, which was constructed by Platonov.


A Novel Kind Of Akns Integrable Couplings And Their Hamiltonian Structures, Yu-Juan Zhang, Wen-Xiu Ma, Ömer Ünsal Jan 2017

A Novel Kind Of Akns Integrable Couplings And Their Hamiltonian Structures, Yu-Juan Zhang, Wen-Xiu Ma, Ömer Ünsal

Turkish Journal of Mathematics

We present a novel hierarchy of AKNS integrable couplings based on a specific semidirect sum of Lie algebras associated with sl$(2)$. By applying the variational identity, we derive a bi-Hamiltonian structure of the resulting coupling systems, thereby showing their Liouville integrability.


More Accurate Jensen-Type Inequalities For Signed Measures Characterized Via Green Function And Applications, Mario Krnic, Josip Pecaric, Mirna Rodic Jan 2017

More Accurate Jensen-Type Inequalities For Signed Measures Characterized Via Green Function And Applications, Mario Krnic, Josip Pecaric, Mirna Rodic

Turkish Journal of Mathematics

In this paper we derive several improved forms of the Jensen inequality, giving the necessary and sufficient conditions for them to hold in the case of the real Stieltjes measure not necessarily positive.The obtained relations are characterized via the Green function. As an application, our main results are employed for constructing some classes of exponentially convex functions and some Cauchy-type means.


Some Notes On $Gqn$ Rings, Long Wang, Junchao Wei Jan 2017

Some Notes On $Gqn$ Rings, Long Wang, Junchao Wei

Turkish Journal of Mathematics

A ring $R$ is called ageneralized quasinormal ring (abbreviated as $GQN$ ring) if $ea∈N(R)$ for each $e∈ E(R)$ and $a∈ N(R)$. The class of $GQN$ rings is a proper generalization of quasinormal rings and $NI$ rings. Many properties of quasinormal rings are extended to $GQN$ rings. For a$GQN$ ring $R$ and $a∈ R$, it is shown that:1) if $a$ is a regular element, then $a$ is a strongly regular element;2) if $a$ is an exchange element, then $a$ is clean;3) if $R$ is a semiperiodic ring with $J(R)\neq N(R)$, then $R$ is commutative;4) if $R$ is an $MVNR$, then $R$ …


Unions And Ideals Of Locally Strongly Porous Sets, Maya Altinok, Oleksiy Dovgoshey, Mehmet Küçükaslan Jan 2017

Unions And Ideals Of Locally Strongly Porous Sets, Maya Altinok, Oleksiy Dovgoshey, Mehmet Küçükaslan

Turkish Journal of Mathematics

For subsets of $\mathbb R^+ = [0,∞)$ we introduce a notion of coherently porous sets as the sets for which the upper limit in the definition of porosity at a point is attained along the same sequence. We prove that the union of two strongly porous at $0$ sets is strongly porous if and only if these sets are coherently porous. This result leads to a characteristic property of the intersection of all maximal ideals contained in the family of strongly porous at $0$ subsets of $\mathbb R^+$. It is also shown that the union of a set $A \subseteq …


Universal Central Extensions Of $\Mathfrak{Sl}(M, N, A)$ Over Associative Superalgebras, Xabier García-Martínez, Manuel Ladra Jan 2017

Universal Central Extensions Of $\Mathfrak{Sl}(M, N, A)$ Over Associative Superalgebras, Xabier García-Martínez, Manuel Ladra

Turkish Journal of Mathematics

We find the universal central extension of the matrix superalgebras $\mathfrak{sl}(m, n, A)$, where $A$ is an associative superalgebra and $m+n = 3, 4$, and its relation with the Steinberg superalgebra $\mathfrak{st}(m, n,A)).$ We calculate $H_2$ $(\mathfrak{sl}(m, n,A))$ and $H_2$ $(\mathfrak{st}(m, n,A))$. Finally, we introduce a new method using the nonabelian tensor product of Lie superalgebras to and the connection between $H_2$ $(\mathfrak{sl}(m, n, A))$ and the cyclic homology of associative superalgebras for $m+n \geq 3$.


Modules Satisfying Double Chain Condition On Nonfinitely Generated Submodules Have Krull Dimension, Maryam Davoudian Jan 2017

Modules Satisfying Double Chain Condition On Nonfinitely Generated Submodules Have Krull Dimension, Maryam Davoudian

Turkish Journal of Mathematics

We prove the result in the title. We study submodules $N$ of a module $M$ such that whenever $\frac{M}{N}$ satisfies the double infinite chain condition so does $M$.Moreover, we observe that an $\alpha $-atomic module, where $\alpha\geq 2$ is an ordinal number, satisfies the previous chain if and only if it satisfies the descending chain condition on nonfinitely generated submodules.


On Focal Curves Of Null Cartan Curves, Hakan Şi̇mşek Jan 2017

On Focal Curves Of Null Cartan Curves, Hakan Şi̇mşek

Turkish Journal of Mathematics

The focal curve, which is determined as the locus of centers of osculatingpseudo-spheres of a null Cartan curve, is investigated in Minkowski(n+2)-space $\mathcal{M}^{n+2}.$ Moreover, a curve called \textit{accelerationfocal curve }of a null Cartan curve is introduced by using a new family of functions.


On Hölder Continuity Of Approximate Solution Maps To Vector Equilibrium Problems, Lam Quoc Anh, Kien Trung Nguyen, Tran Ngoc Tam Jan 2017

On Hölder Continuity Of Approximate Solution Maps To Vector Equilibrium Problems, Lam Quoc Anh, Kien Trung Nguyen, Tran Ngoc Tam

Turkish Journal of Mathematics

In this article, we considerparametric vector equilibrium problems in normed spaces. Sufficientconditions for Hölder continuity of approximate solution mappingswhere they are set-valued are established. As applications of theseresults, the Hölder continuity of the approximate solutionmappings for vector optimization problems and vector variationalinequalities are derived at the end of the paper. Our results arenew and include the existing ones in the literature.


Evaluation Of Euler-Like Sums Via Hurwitz Zeta Values, Ayhan Di̇l, Istvan Mezo, Mehmet Cenkci̇ Jan 2017

Evaluation Of Euler-Like Sums Via Hurwitz Zeta Values, Ayhan Di̇l, Istvan Mezo, Mehmet Cenkci̇

Turkish Journal of Mathematics

In this paper we collect two generalizations of harmonic numbers (namelygeneralized harmonic numbers and hyperharmonic numbers) under one roof.Recursion relations, closed-form evaluations, and generating functions of thisunified extension are obtained. In light of this notion we evaluate someparticular values of Euler sums in terms of odd zeta values. We alsoconsider the noninteger property and some arithmetical aspects of this unifiedextension.


Generalization Of The Gauss--Lucas Theorem For Bicomplex Polynomials, Mahmood Bidkham, Sara Ahamadi Jan 2017

Generalization Of The Gauss--Lucas Theorem For Bicomplex Polynomials, Mahmood Bidkham, Sara Ahamadi

Turkish Journal of Mathematics

The aim of this paper is to extend the domain of the Gauss—Lucas theorem from the set of complex numbers to the set of bicomplex numbers. We also discuss a bicomplex version of another compact generalization of the Gauss—Lucas theorem.


On Armendariz-Like Properties In Amalgamated Algebras Along Ideals, Abdeslam Mimouni, Najib Mahdou, Mounir El Ourrachi Jan 2017

On Armendariz-Like Properties In Amalgamated Algebras Along Ideals, Abdeslam Mimouni, Najib Mahdou, Mounir El Ourrachi

Turkish Journal of Mathematics

Let $f: A\rightarrow B$ be a ring homomorphism and $J$ be an ideal of $B$. In this paper, we investigate the transfer of Armendariz-like properties to the amalgamation of $A$ with $B$ along $J$ with respect to $f$ (denoted by $A\bowtie^fJ)$ introduced and studied by D'Anna, Finocchiaro, and Fontana in 2009. Our aim is to provide necessary and sufficient conditions for $A\bowtie^fJ$ to be an Armendariz ring, nil-Armendariz ring, and weak Armendariz ring.


Extension Of The Darboux Frame Into Euclidean 4-Space And Its Invariants, Mustafa Düldül, Bahar Uyar Düldül, Nuri̇ Kuruoğlu, Ertuğrul Özdamar Jan 2017

Extension Of The Darboux Frame Into Euclidean 4-Space And Its Invariants, Mustafa Düldül, Bahar Uyar Düldül, Nuri̇ Kuruoğlu, Ertuğrul Özdamar

Turkish Journal of Mathematics

In this paper, by considering a Frenet curve lying on an oriented hypersurface, we extend the Darboux frame field into Euclidean 4-space $\mathbb{E}^4$. Depending on the linear independency of the curvature vector with the hypersurface's normal, we obtain two cases for this extension. For each case, we obtain some geometrical meanings of new invariants along the curve on the hypersurface. We also give the relationships between the Frenet frame curvatures and Darboux frame curvatures in $\mathbb{E}^4$. Finally, we compute the expressions of the new invariants of a Frenet curve lying on an implicit hypersurface.


Optimality Conditions Via Weak Subdifferentials In Reflexive Banach Spaces, Sara Hassani, Musa Mammadov, Mina Jamshidi Jan 2017

Optimality Conditions Via Weak Subdifferentials In Reflexive Banach Spaces, Sara Hassani, Musa Mammadov, Mina Jamshidi

Turkish Journal of Mathematics

In this paper the relation between the weak subdifferentials and the directional derivatives, as well as optimality conditions for nonconvex optimization problems in reflexive Banach spaces, are investigated. It partly generalizes several related results obtained for finite dimensional spaces.


Some Fixed Point Theorems For Single Valued Strongly Contractive Mappings In Partially Ordered Ultrametric And Non-Archimedean Normed Spaces, Hamid Mamghaderi, Hashem Parvaneh Masiha, Meraj Hosseini Jan 2017

Some Fixed Point Theorems For Single Valued Strongly Contractive Mappings In Partially Ordered Ultrametric And Non-Archimedean Normed Spaces, Hamid Mamghaderi, Hashem Parvaneh Masiha, Meraj Hosseini

Turkish Journal of Mathematics

Let $ (X,d,\preceq) $ be a partially ordered ultrametric space and $ f:X\to X $ a single valued mapping. We obtain sufficient conditions for the existence of a fixed point for the strongly contractive mapping $ f $. We also investigate the existence of a fixed point for strongly contractive mappings defined on partially ordered non-Archimedean normed spaces under the same conditions. Finally, we give some examples to discuss the assumptions of the theorems.


Extensions Of Quasipolar Rings, Orhan Gürgün Jan 2017

Extensions Of Quasipolar Rings, Orhan Gürgün

Turkish Journal of Mathematics

An associative ring with identity is called quasipolar provided that for each $a\in R$ there exists an idempotent $p\in R$ such that $p\in comm^2(a)$, $a+p\in U(R)$ and $ap\in R^{qnil}$. In this article, we introduce the notion of quasipolar general rings (with or without identity). Some properties of quasipolar general rings are investigated. We prove that a general ring $I$ is quasipolar if and only if every element $a\in I$ can be written in the form $a=s+q$ where $s$ is strongly regular, $s\in comm^2(a)$, $q$ is quasinilpotent, and $sq=qs=0$. It is shown that every ideal of a quasipolar general ring is …