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Physical Sciences and Mathematics Commons™
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- Keyword
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- (pre)cover (2)
- (pre)envelope (2)
- Bergman space (2)
- Invariant subspace (2)
- Mean curvature (2)
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- (anti)Hermitian metric (1)
- (finitely generated) abelian groups (1)
- A quadratic reversible system with one center of genus one (1)
- ARFIMA model (1)
- Abelian category (1)
- Absolute irreducibility (1)
- Action (1)
- Adams spectral sequence (1)
- Almost complex structure (1)
- Analytic tensor field (1)
- Arbitrary information source (1)
- Artinian module (1)
- Associate ring (1)
- Auslander class (1)
- B. Y. Chen inequality (1)
- Banach module (1)
- Bases of cosines and sines (1)
- Bass class (1)
- Beurling's theorem (1)
- Bifurcation of limit cycles (1)
- Bloch space (1)
- Blow-up (1)
- Bootstrap (1)
- Brauer-Wall Groups (1)
- CD_0(K)-spaces (1)
Articles 1 - 30 of 55
Full-Text Articles in Physical Sciences and Mathematics
A Fixed Point Theorem For A Compact And Connected Set In Hilbert Space, Hülya Duru
A Fixed Point Theorem For A Compact And Connected Set In Hilbert Space, Hülya Duru
Turkish Journal of Mathematics
Let (H,) be a real Hilbert space and let K be a compact and connected subset of H. We show that every continuous mapping T:K \rightarrow K satisfying a mild condition has a fixed point.
Covers And Envelopes With Respect To A Semidualizing Module, Xiaoguang Yan, Xiaosheng Zhu
Covers And Envelopes With Respect To A Semidualizing Module, Xiaoguang Yan, Xiaosheng Zhu
Turkish Journal of Mathematics
Let R be a commutative ring and C be a semidualizing R-module. For a given class of R-modules Q, we define a class Q_C by M \in Q_C \Leftrightarrow Hom_R(C,M) \in Q. We prove that if Q \subseteq (R) is a Kaplansky class and closed under direct sums, then Q_C^{\bot} is special preenveloping. As corollaries, we can show that p_C^{n \bot} and f_C^{n \bot} are both special preenveloping. Finally, we show that I_C^n is covering, I_C^{n \bot} is enveloping and special preenveloping provided R is Noetherian.
Combinatorial Results For Order-Preserving And Order-Decreasing Transformations, Gonca Ayik, Hayrullah Ayik, Meti̇n Koç
Combinatorial Results For Order-Preserving And Order-Decreasing Transformations, Gonca Ayik, Hayrullah Ayik, Meti̇n Koç
Turkish Journal of Mathematics
Let O_n and C_n be the semigroup of all order-preserving transformations and of all order-preserving and order-decreasing transformations on the finite set X_n={1,2,\ldots ,n}, respectively. Let \fix (\alpha )={x\in X_n:x\alpha =x} for any transformation \alpha. In this paper, for any Y\subseteq X_n, we find the cardinalities of the sets O_{n,Y}={\alpha\in O_n:\fix (\alpha)=Y} and C_{n,Y}={\alpha\in C_n: \fix (\alpha )=Y}. Moreover, we find the numbers of transformations of O_n and C_n with r fixed points.
Weak-Projective Dimensions, Mohammad Javad Nikmehr, Zahra Poormahmood, Reza Nikandish
Weak-Projective Dimensions, Mohammad Javad Nikmehr, Zahra Poormahmood, Reza Nikandish
Turkish Journal of Mathematics
In this paper, the notions of weak-projective modules and weak-projective dimension over commutative domain R are given. It is shown that over semisimple rings with weak global dimension 1, these modules are equivalent to weak-injective modules. The weak-projective dimension measures how far away a domain is from being a Prüfer domain. Several properties of these modules are also presented.
Analysis Of A Differential Equation Model Of Hiv Infection Of Cd4^+ T-Cells With Saturated Reverse Function, Xiangyun Shi, Gang Li, Xueyong Zhou, Xinyu Song
Analysis Of A Differential Equation Model Of Hiv Infection Of Cd4^+ T-Cells With Saturated Reverse Function, Xiangyun Shi, Gang Li, Xueyong Zhou, Xinyu Song
Turkish Journal of Mathematics
In this paper, an ordinary differential equation model of HIV infection of CD4^+ T-cells with saturated reverse function is studied. We prove that if the basic reproduction number R_0
Conjugate Convolution And Characterizations Of Inner Amenable Locally Compact Groups, Bahram Mohammadzadeh
Conjugate Convolution And Characterizations Of Inner Amenable Locally Compact Groups, Bahram Mohammadzadeh
Turkish Journal of Mathematics
For locally compact group G, we give some characterizations of inner amenability of G by conjugate convolution operations. Moreover, we study multiples of positive elements in group algebra L^1(G), whenever G is inner amenable.
A Beurling-Type Theorem In Bergman Spaces, Ali Abkar
A Beurling-Type Theorem In Bergman Spaces, Ali Abkar
Turkish Journal of Mathematics
It is known that Beurling's theorem concerning invariant subspaces is not true in the Bergman space (in contrast to the Hardy space case). However, Aleman, Richter, and Sundberg proved that every cyclic invariant subspace in the Bergman space \lpad, 0
A Class Of Generalized Shannon-Mcmillan Theorems For Arbitrary Discrete Information Source, Kangkang Wang
A Class Of Generalized Shannon-Mcmillan Theorems For Arbitrary Discrete Information Source, Kangkang Wang
Turkish Journal of Mathematics
In this study, a class of strong limit theorems for the relative entropy densities of random sum of arbitrary information source are discussed by constructing the joint distribution and nonnegative super martingales. As corollaries, some Shannon-McMillan theorems for arbitrary information source, mth-order Markov information source and non-memory information source are obtained and some results for the discrete information source which have been obtained by authors are extended.
Geometrical Objects Associated To A Substructure, Fatma Özdemi̇r, Mircea Craşmareanu
Geometrical Objects Associated To A Substructure, Fatma Özdemi̇r, Mircea Craşmareanu
Turkish Journal of Mathematics
Several geometric objects, namely global tensor fields of (1,1)-type, linear connections and Riemannian metrics, associated to a given substructure on a splitting of tangent bundle, are studied. From the point of view of lifting to entire manifold, two types of polynomial substructures are distinguished according to the vanishing of not of the sum of the coefficients. Conditions of parallelism for the extended structure with respect to some remarkable linear connections are given in two forms, firstly in a global description and secondly using the decomposition in distributions. A generalization of both Hermitian and anti-Hermitian geometry is proposed.
On Generalized Witt Algebras In One Variable, Ki Bong Nam, Jonathan Pakianathan
On Generalized Witt Algebras In One Variable, Ki Bong Nam, Jonathan Pakianathan
Turkish Journal of Mathematics
We study a class of infinite dimensional Lie algebras called generalized Witt algebras (in one variable). These include the classical Witt algebra and the centerless Virasoro algebra as important examples. We show that any such generalized Witt algebra is a semisimple, indecomposable Lie algebra which does not contain any abelian Lie subalgebras of dimension greater than one. We develop an invariant of these generalized Witt algebras called the spectrum, and use it to show that there exist infinite families of nonisomorphic, simple, generalized Witt algebras and infinite families of nonisomorphic, nonsimple, generalized Witt algebras. We develop a machinery that can …
On Generalized (\Alpha,\Beta)-Derivations Of Semiprime Rings, Faisal Ali, Muhammad Anwar Chaudhry
On Generalized (\Alpha,\Beta)-Derivations Of Semiprime Rings, Faisal Ali, Muhammad Anwar Chaudhry
Turkish Journal of Mathematics
We investigate some properties of generalized (\alpha,\beta)-derivations on semiprime rings. Among some other results, we show that if g is a generalized (\alpha,\beta)-derivation, with associated (\alpha,\beta)-derivation \delta, on a semiprime ring R such that [g(x),\alpha(x)]=0 for all x\in R, then \delta(x)[y,z]=0 for all x,y,z\in R and \delta is central. We also show that if \alpha,\nu,\tau are endomorphisms and \beta,\mu are automorphisms of a semiprime ring R and if R has a generalized (\alpha,\beta)-derivation g, with associated (\alpha,\beta)-derivation \delta, such that g([\mu(x),w(y)])=[\nu(x),w(y)]_{\alpha,\tau}, where w:R\rightarrow R is commutativity preserving, then [y,z]\delta(w(p))=0 for all y,z,p\in R.
Approximation By Complex Potentials Generated By The Gamma Function, Sorin G. Gal
Approximation By Complex Potentials Generated By The Gamma Function, Sorin G. Gal
Turkish Journal of Mathematics
In this paper we find the exact orders of approximation of analytic functions by the complex versions of several potentials (including the Flett potential) generated by the Gamma function and by some singular integrals.
Existence Of Mild Solutions For Abstract Mixed Type Semilinear Evolution Equations, Hong-Bo Shi, Wan-Tong Li, Hong-Rui Sun
Existence Of Mild Solutions For Abstract Mixed Type Semilinear Evolution Equations, Hong-Bo Shi, Wan-Tong Li, Hong-Rui Sun
Turkish Journal of Mathematics
This paper is concerned with the existence of global mild solutions and positive mild solutions to initial value problem for a class of mixed type semilinear evolution equations with noncompact semigroup in Banach spaces. The main method is based on a new fixed point theorem with respect to convex-power condensing operator.
Weingarten Quadric Surfaces In A Euclidean 3-Space, Min Hee Kim, Dae Won Yoon
Weingarten Quadric Surfaces In A Euclidean 3-Space, Min Hee Kim, Dae Won Yoon
Turkish Journal of Mathematics
In this paper, we study quadric surfaces in a Euclidean 3-space. Furthermore, we classify quadric surfaces in a Euclidean 3-space in terms of the Gaussian curvature and the mean curvature.
A Fredholm Alternative-Like Result On Power Bounded Operators, Ali̇ Ülger, Onur Yavuz
A Fredholm Alternative-Like Result On Power Bounded Operators, Ali̇ Ülger, Onur Yavuz
Turkish Journal of Mathematics
Let X be a complex Banach space and T:X\rightarrow X be a power bounded operator, i.e., \sup_{n \geq 0}\ T^n\
Rotational Embeddings In E^4 With Pointwise 1-Type Gauss Map, Kadri̇ Arslan, Bengü Kiliç Bayram, Betül Bulca, Young Ho Ki̇m, Cengi̇zhan Murathan, Günay Öztürk
Rotational Embeddings In E^4 With Pointwise 1-Type Gauss Map, Kadri̇ Arslan, Bengü Kiliç Bayram, Betül Bulca, Young Ho Ki̇m, Cengi̇zhan Murathan, Günay Öztürk
Turkish Journal of Mathematics
In the present article we study the rotational embedded surfaces in E^4. The rotational embedded surface was first studied by G. Ganchev and V. Milousheva as a surface in E^4. The Otsuki (non-round) sphere in E^4 is one of the special examples of this surface. Finally, we give necessary and sufficient conditions for the flat Ganchev-Milousheva rotational surface to have pointwise 1-type Gauss map.
B. Y. Chen Inequalities For Submanifolds Of A Riemannian Manifold Of Quasi-Constant Curvature, Ci̇han Özgür
B. Y. Chen Inequalities For Submanifolds Of A Riemannian Manifold Of Quasi-Constant Curvature, Ci̇han Özgür
Turkish Journal of Mathematics
In this paper, we prove B. Y. Chen inequalities for submanifolds of a Riemannian manifold of quasi-constant curvature, i.e., relations between the mean curvature, scalar and sectional curvatures, Ricci curvatures and the sectional curvature of the ambient space. The equality cases are considered.
Properties Of Rd-Projective And Rd-Injective Modules, Lixin Mao
Properties Of Rd-Projective And Rd-Injective Modules, Lixin Mao
Turkish Journal of Mathematics
In this paper, we first study RD-projective and RD-injective modules using, among other things, covers and envelopes. Some new characterizations for them are obtained. Then we introduce the RD-projective and RD-injective dimensions for modules and rings. The relations between the RD-homological dimensions and other homological dimensions are also investigated.
Homology With Respect To A Kernel Transformation, Seyed Naser Hosseini, Mohammad Zaher Kazemi Baneh
Homology With Respect To A Kernel Transformation, Seyed Naser Hosseini, Mohammad Zaher Kazemi Baneh
Turkish Journal of Mathematics
In this article we first give the relations between commonly used images of a morphism in a category. We then investigate d-homology in a category with certain properties, for a kernel transformation d. In particular, we show that, in an abelian category, d-homology, where d is induced by the subtraction operation, is the standard homology and that in more general categories the d-homology for a trivial d is zero. We also compute through examples the d-homology for certain kernel transformations d in such categories as R-modules, abelian groups and short exact sequences of R-modules. Finally, we characterize kernel transformations in …
Coverings Of Lie Groupoids, İlhan İçen, M. Habi̇l Gürsoy, A. Fati̇h Özcan
Coverings Of Lie Groupoids, İlhan İçen, M. Habi̇l Gürsoy, A. Fati̇h Özcan
Turkish Journal of Mathematics
In this work we constitute the category of coverings of the Lie fundamental groupoid associated with a connected smooth manifold. We show that this category is equivalent to the category of universal coverings of a connected smooth manifold. In addition, we prove the equivalence of the category of coverings of a Lie groupoid and the category of actions of this Lie groupoid on a connected smooth manifold. Also we present two side results related to actions of Lie groupoids on the manifolds and coverings of Lie groupoids.
A Note On Weighted A_P(G)-Modules, Serap Öztop
A Note On Weighted A_P(G)-Modules, Serap Öztop
Turkish Journal of Mathematics
Let G be a locally compact abelian group and w be a weight function on G. In this paper, we show that the space A_{p,w}(G) is a Banach module over the Figà-Talamanca Herz algebra A_p(G) and study the multiplier space from A_p(G) to A_{p,w}(G).
Invariant Subspace Problem For Positive L-Weakly And M-Weakly Compact Operators, Cevri̇ye Tonyali, Erdal Bayram
Invariant Subspace Problem For Positive L-Weakly And M-Weakly Compact Operators, Cevri̇ye Tonyali, Erdal Bayram
Turkish Journal of Mathematics
In this paper, we show that positive L-weakly and M-weakly compact operators on some real Banach lattices have a non-trivial closed invariant subspace. Also, we prove that any positive L-weakly (or M-weakly) compact operator T:E \rightarrow E\ has a non-trivial closed invariant subspace if there exists a Dunford-Pettis operator S:E \rightarrow E satisfying 0 \leq T \leq S, where E is Banach lattice.
Products Of Multiplication, Composition And Differentiation Between Weighted Bergman-Nevanlinna And Bloch-Type Spaces, Ajay K. Sharma
Products Of Multiplication, Composition And Differentiation Between Weighted Bergman-Nevanlinna And Bloch-Type Spaces, Ajay K. Sharma
Turkish Journal of Mathematics
Let \varphi and \psi be holomorphic maps on D such that \varphi ( D ) \subset D . Let C_{\varphi} , M_{\psi} and D be the composition, multiplication and differentiation operators, respectively. In this paper, we consider linear operators induced by products of these operators from Bergman-Nevanlinna spaces A^{\beta}_N to Bloch-type spaces. In fact, we prove that these operators map A^{\beta}_N compactly into Bloch-type spaces if and only if they map A^{\beta}_N boundedly into these spaces.
Hypersurfaces With Constant Mean Curvature In A Real Space Form, Shichang Shu, Sanyang Liu
Hypersurfaces With Constant Mean Curvature In A Real Space Form, Shichang Shu, Sanyang Liu
Turkish Journal of Mathematics
Let M^n be an n\(n \geq 3)-dimensional complete connected and oriented hypersurface in M^{n+1}(c)(c \geq 0) with constant mean curvature H and with two distinct principal curvatures, one of which is simple. We show that (1) if c=1 and the squared norm of the second fundamental form of M^n satisfies a rigidity condition (1.3), then M^n is isometric to the Riemannian product S^1(\sqrt{1-a^2}) \times S^{n-1}(a); (2) if c=0, H \neq 0 and the squared norm of the second fundamental form of M^n satisfies S \geq n^2H^2/(n-1), then M^n is isometric to the Riemannian product S^{n-1}(a)\times R or S^1(a) \times R^{n-1}
Krull Dimension Of Types In A Class Of First-Order Theories, Domenico Zambella
Krull Dimension Of Types In A Class Of First-Order Theories, Domenico Zambella
Turkish Journal of Mathematics
We study a class of first-order theories whose complete quantifier-free types with one free variable either have a trivial positive part or are isolated by a positive quantifier-free formula---plus a few other technical requirements. The theory of vector spaces and the theory fields are examples. We prove the amalgamation property and the existence of a model-companion. We show that the model-companion is strongly minimal. We also prove that the length of any increasing sequence of prime types is bounded, so every formula has finite Krull dimension.
Blow-Up Time For A Semilinear Parabolic Equation With Variable Reaction, Theodore Kouassi Boni, Remi Kouadio Kouakou
Blow-Up Time For A Semilinear Parabolic Equation With Variable Reaction, Theodore Kouassi Boni, Remi Kouadio Kouakou
Turkish Journal of Mathematics
In this paper, we address the solution of a semilinear heat equation with variable reaction subject to Dirichlet boundary conditions and nonnegative initial datum. Under some assumptions, we show that the solution of the above problem blows up in a finite time, and its blow-up time goes to that of the solution of a certain differential equation. Finally, we give some numerical results to illustrate our analysis.
Jackknife And Bootstrap With Cycling Blocks For The Estimation Of Fractional Parameter In Arfima Model, Lorenc Ekonomi, Argjir Butka
Jackknife And Bootstrap With Cycling Blocks For The Estimation Of Fractional Parameter In Arfima Model, Lorenc Ekonomi, Argjir Butka
Turkish Journal of Mathematics
One of most important problems concerning the ARFIMA time series model is the estimation of fractional parameter d. Various methods have been used to solve this problem, such as the log-periodogram regression of a process. In this article we propose two jackknife and bootstrap methods, which aid in the estimation of fractional parameter d. These methods involve non-overlapping blocks and moving blocks with random starting point and length. We have conducted several simulations and the results show that the estimations obtained are very close to the real parameter value.
Some Products Involving The Fourth Greek Letter Family Element \Tilde{\Delta}_S In The Adams Spectral Sequence, Xiu-Gui Liu, He Wang
Some Products Involving The Fourth Greek Letter Family Element \Tilde{\Delta}_S In The Adams Spectral Sequence, Xiu-Gui Liu, He Wang
Turkish Journal of Mathematics
Let p be an odd prime and A be the mod p Steenrod algebra. For computing the stable homotopy groups of spheres with the classical Adams spectral sequence, we must compute the E_2-term of the Adams spectral sequence, Ext_A^{\ast,\ast} (Z_p,Z_p). In this paper we prove that in the cohomology of A, the product k_0 h_n \tilde \delta _{s + 4} \in Ext_A^{s + 7, t(s,n) + s} (Z_p, Z_p), is nontrivial for n \geq 5, and trivial for n=3, 4, where \tilde\delta_{s + 4} is actually \tilde\alpha_{s + 4}^{(4)} described by Wang and Zheng, p \geq 11, 0 \leq s < p - 4 and t(s,n)=2(p-1)[(s + 2) + (s + 4)p + (s + 3)p^2 + (s + 4)p^3 + p^n].
Graded Multiplication Modules And The Graded Ideal \Theta_G (M), Shahabaddin Ebrahimi Atani, Reza Ebrahimi Atani
Graded Multiplication Modules And The Graded Ideal \Theta_G (M), Shahabaddin Ebrahimi Atani, Reza Ebrahimi Atani
Turkish Journal of Mathematics
Let G be a group and let R be a G-graded commutative ring. For a graded R-module M, the notion of the associated graded ideal \theta_g (M) of R is defined. It is proved that the graded ideal \theta_g (M) is important in the study of graded multiplication modules. Among various application given, the following results are proved: if M is a graded faithful multiplication module, then \theta_g (M) is an idempotent graded multiplication ideal of R such that \theta_g (\theta_g (M)) = \theta_g (M), and every graded representable multiplication R-module is finitely generated.
Slant Lightlike Submanifolds Of Indefinite Kenmotsu Manifolds, Ram Gupta, Sharfuddin Ahamad
Slant Lightlike Submanifolds Of Indefinite Kenmotsu Manifolds, Ram Gupta, Sharfuddin Ahamad
Turkish Journal of Mathematics
In this paper, we introduce the notion of a slant lightlike submanifold of an indefinite Kenmotsu manifold. We provide a non-trivial example and obtain necessary and sufficient conditions for the existence of a slant lightlike submanifold. Also, we give an example of a minimal slant lightlike submanifold of R_2^{9} and prove some characterization theorems.