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Full-Text Articles in Physical Sciences and Mathematics

The Verlinde Algebra Is Twisted Equivariant K-Theory, Daniel S. Freed Jan 2001

The Verlinde Algebra Is Twisted Equivariant K-Theory, Daniel S. Freed

Turkish Journal of Mathematics

The Verlinde algebra, which mathematically appears in the theory of loop groups and is related to moduli spaces of bundles over curves, turns out to be describable in terms of K-theory. This is a joint discovery with M. Hopkins and C. Teleman. Here we explain in heuristic terms how this fits naturally into ideas about the Chern-Simons topological field theory.


On The Expansions In Eigenfunctions Of Hill's Operator, Fi̇li̇z Aras, Gusei̇n Sh Gusei̇nov Jan 2001

On The Expansions In Eigenfunctions Of Hill's Operator, Fi̇li̇z Aras, Gusei̇n Sh Gusei̇nov

Turkish Journal of Mathematics

In this paper we show how one can deduce the Titchmarsh expansion formula in eigenfunctions of Hill's operator from the Gel'fand expansion formula.


Global Convergence For Discrete Dynamical Systems And Forward Neural Networks, Asuman G. Aksoy, Mario Martelli Jan 2001

Global Convergence For Discrete Dynamical Systems And Forward Neural Networks, Asuman G. Aksoy, Mario Martelli

Turkish Journal of Mathematics

Using a theoretical result regarding the global stability of discrete dynamical systems of lower triangular form, we establish convergence properties of forward neural networks when the neuron response functions fail to be continuous.


On Modified Baskakov Operators On Weighted Spaces, Nurhayat İspi̇r Jan 2001

On Modified Baskakov Operators On Weighted Spaces, Nurhayat İspi̇r

Turkish Journal of Mathematics

The author presents a modification of the Baskakov operator for the intervals [0,b_{n}], where b_{n} is an increasing sequence of positive numbers with either finite or infinite limit. Convergence properties of such an operator for continuous and differentiable functions in weighted space are established.


A General Fixed Point Theorem For Weakly Compatible Mappings In Compact Metric Spaces, Valeriu Popa Jan 2001

A General Fixed Point Theorem For Weakly Compatible Mappings In Compact Metric Spaces, Valeriu Popa

Turkish Journal of Mathematics

A general fixed point theorem for weakly compatible mappings satisfying an implicit relation in compact metric spaces is proved generalizing the results by [1],[3],[13],[14] and others.


Some Applications Of The Lattice Finite Representability In Spaces Of Measurable Functions, P. Gomez Palaci̇o, J. A. Lopez Molina, M. J. Rivera Jan 2001

Some Applications Of The Lattice Finite Representability In Spaces Of Measurable Functions, P. Gomez Palaci̇o, J. A. Lopez Molina, M. J. Rivera

Turkish Journal of Mathematics

We study the lattice finite representability of the Bochner space L_p(\mu_1,L_q(\mu_2)) in \ell_p{\ell_q}, 1 \le p,q < \infty, and then we characterize the ideal of the operators which factor through a lattice homomorphism between L_{\infty}(\mu) and L_p(\mu_1,L_q(\mu_2)).


Absolutely Representing Systems Of Exponentials In The Spaces Of Infinitely-Differentiable Functions And Extendability In The Sense Of Whitney, Yu. F. Korobeinik Jan 2001

Absolutely Representing Systems Of Exponentials In The Spaces Of Infinitely-Differentiable Functions And Extendability In The Sense Of Whitney, Yu. F. Korobeinik

Turkish Journal of Mathematics

Let Q be a compactum in~\mathbb{R}^p, p\geqslant1, such that int Q\neq\varnothing and Q=\overline{ int Q}. Denote by C^{\infty}[Q] the space of functions from C^{\infty}( int Q) uniformly continuous in int Q together with all their partial derivatives. The conditions of the existence of absolutely representing systems of exponentials with purely imaginary exponents in the space C^{\infty}[Q] and some of its subspaces of Denjoy--Carleman type are investigated. It is also proved under rather general assumptions that there is no such absolutely representing systems in the space E(G)=\operatornamewithlimits{proj}\limits_ {\overleftarrow {Q\in \mathcal{F}_G}}E[Q] where G is an arbitrary open set in~\mathbb{R}^p, E[Q] is C^{\infty}[Q] …


L^P Boundedness Of A Class Of Singular Integral Operators With Rough Kernels, Ahmad Al-Salman, Hussain Al-Quassem Jan 2001

L^P Boundedness Of A Class Of Singular Integral Operators With Rough Kernels, Ahmad Al-Salman, Hussain Al-Quassem

Turkish Journal of Mathematics

In this paper, we study the L^p mapping properties of singular integral operators with kernels belonging to certain block spaces. These operators have singularities along sets of the form {x=\Phi ( y )y^'} where \Phi satisfies certain growth conditions. Our results improve as well as extend previously known results on singular integrals.


Sections Of Lefschetz Fibrations And Stein Fillings, Andras I. Stipsicz Jan 2001

Sections Of Lefschetz Fibrations And Stein Fillings, Andras I. Stipsicz

Turkish Journal of Mathematics

Using Eliashberg's theorem about Stein fillings of S^3 we prove that a section of a Lefschetz fibration over S^2 has nonnegative square. This observation, in particular, implies that the identity element 1\in \Gamma _g ^1 in the mapping class group of a genus-g surface with one boundary component cannot be written as a product of positive Dehn twists.


The Canonical Class Of A Symplectic Four Manifold, Ronald Fintushel, Ronald Stern Jan 2001

The Canonical Class Of A Symplectic Four Manifold, Ronald Fintushel, Ronald Stern

Turkish Journal of Mathematics

In this article we present examples of simply connected symplectic 4-manifolds X whose canonical classes are represented by complicated disjoint unions of symplectic submanifolds of X: Theorem. Given finite collections {g_i}, {m_i}, i=1,...,n, of positive integers, there is a minimal symplectic simply connected 4-manifold X whose canonical class is represented by a disjoint union of embedded symplectic surfaces K ~ S_{g_1,1} « ... « S_{g_1,m_1} « ... « S_{g_n,1} «... « S{g_n,m_n} where S_{g_i,j} is a surface of genus g_i. Furthermore, c_1^2(X) = c_h(X) - (2+ b) where b= S{i=1}^n m_i is the total number of connected components of the …


G-Bundles On Abelian Surfaces, Hyperk\"Aler Manifolds, And Stringy Hodge Numbers, Jim Bryan, Ron Donagi, Naichung Conan Leung Jan 2001

G-Bundles On Abelian Surfaces, Hyperk\"Aler Manifolds, And Stringy Hodge Numbers, Jim Bryan, Ron Donagi, Naichung Conan Leung

Turkish Journal of Mathematics

We study the moduli space M_{G} (A) of flat G-bundles on an Abelian surface A, where G is a compact, simple, simply connected, connected Lie group. Equivalently, M_{G} (A) is the (coarse) moduli space of s-equivalence classes of holomorphic semi-stable G^{\cnums }-bundles with trivial Chern classes. M_{G} (A) has the structure of a hyperk\"ahler orbifold. We show that when G is Sp(n) or SU (n), M_{G} (A) has a natural hyperk\"ahler desingularization which we exhibit as a moduli space of G^{\cnums }-bundles with an altered stability condition. In this way, we obtain the two known families of hyperk\"ahler manifolds, the …


On The Tautological Ring Of \Bar{\Mathcal{M}}_{G,N}, Tom Graber, Ravi Vakil Jan 2001

On The Tautological Ring Of \Bar{\Mathcal{M}}_{G,N}, Tom Graber, Ravi Vakil

Turkish Journal of Mathematics

We prove that the dimension 0 part of the tautological ring of the moduli space of stable pointed curves is one-dimensional. This provides the first genus-free evidence for a conjecture of Faber and Pandharipande that the tautological ring of the moduli space is Gorenstein, answering in the affirmative a question of Hain and Looijenga.


Formula For The Highly Regularized Trace Of The Sturm-Liouville Operator With Unbounded Operator Coefficients Having Singularity, İnci̇ Albayrak, Oya Baykal, Erdal Gül Jan 2001

Formula For The Highly Regularized Trace Of The Sturm-Liouville Operator With Unbounded Operator Coefficients Having Singularity, İnci̇ Albayrak, Oya Baykal, Erdal Gül

Turkish Journal of Mathematics

In this work, a formula for the n^{th} regularized trace of the Sturm-Liouville operator with unbounded operator coefficients having singularity is obtained


Remarks On The Paper "On The Commutant Of The Ideal Centre", Şafak Alpay, Bahri̇ Turan Jan 2001

Remarks On The Paper "On The Commutant Of The Ideal Centre", Şafak Alpay, Bahri̇ Turan

Turkish Journal of Mathematics

We continue with the work started in [4] and give a new sufficient condition on Riesz spaces having topologically full centres for Z^{\sim}(E)_C=Orth(E^{\sim}) to hold.


On The Centroid Of The Prime Gamma Rings Ii, Mehmet Ali̇ Öztürk, Young Bae Jun Jan 2001

On The Centroid Of The Prime Gamma Rings Ii, Mehmet Ali̇ Öztürk, Young Bae Jun

Turkish Journal of Mathematics

The aim of this paper is to study the properities of the extended centroid of the prime \Gamma-rings. Main results are the following theorems: (1) Let M be a simple \Gamma-ring with unity. Suppose that for some a\neq 0 in M we have a\gamma_{1} x\gamma_{2} a\beta_{1} y\beta_{2}a = a\beta_{1} y\beta_{2} a\gamma_{1} x\gamma_{2}a for all x, y\in M and \gamma_{1} ,\gamma_{2} ,\beta_{1} ,\beta_{2} \in \Gamma. Then M is isomorphic onto the \Gamma-ring D_{n,m}, where D_{n,m} is the additive abelian group of all rectangular matrices of type n\times m over a division ring D and \Gamma is a nonzero subgroup of the …


Characterizations Of Matroid Via Ofr-Sets, Talal Ali̇ Al-Hawary Jan 2001

Characterizations Of Matroid Via Ofr-Sets, Talal Ali̇ Al-Hawary

Turkish Journal of Mathematics

The aim of this paper is to introduce the class of OFR-sets as the sets that are the intersection of an open set and a feeble-regular set. Several classes of matroids are studied via the new concept. New decompositions of strong maps are provided.


Diagonal Lift In The Cotangent Bundle And Its Applications, Sezgi̇n Akbulut, Murat Özdemi̇r, Ari̇f A. Salimov Jan 2001

Diagonal Lift In The Cotangent Bundle And Its Applications, Sezgi̇n Akbulut, Murat Özdemi̇r, Ari̇f A. Salimov

Turkish Journal of Mathematics

The purpose of this paper is to define a diagonal lift ^{\mathcal{D }}g of a Riemannian metric g of a manifold M_{n} to the cotangent bundle T^{*}(M_{n}) of M_{n}, to associate with ^{\mathcal{D}}g an Levi-Civita connection of T^{*}(M_{n}) in a natural way and to investigate applications of the diagonal lifts.


A Special Quasi-Linear Mapping And Its Degree, Aki̇f Abbasov Jan 2000

A Special Quasi-Linear Mapping And Its Degree, Aki̇f Abbasov

Turkish Journal of Mathematics

In this article, for the purpose of expanding to the mappings between Banach manifolds, a degree is determined in for the mappings between Banach spaces, which are from the obvious class.


Strongly Prime Ideals In Cs-Rings, Gonca Güngöroğlu Jan 2000

Strongly Prime Ideals In Cs-Rings, Gonca Güngöroğlu

Turkish Journal of Mathematics

We study and characterize strongly prime right ideals in CS-rings.


On Non-Homogeneous Riemann Boundary Value Problem, Kadi̇r Kutlu Jan 2000

On Non-Homogeneous Riemann Boundary Value Problem, Kadi̇r Kutlu

Turkish Journal of Mathematics

In this paper we consider non-homogeneous Riemann boundary value problem with unbounded oscillating coefficients on a class of open rectifiable Jordan curve.


On The Linearity Of Certain Mapping Class Groups, Mustafa Korkmaz Jan 2000

On The Linearity Of Certain Mapping Class Groups, Mustafa Korkmaz

Turkish Journal of Mathematics

S. Bigelow proved that the braid groups are linear. That is, there is a faithful representation of the braid group into the general linear group of some field. Using this, we deduce from previously known results that the mapping class group of a sphere with punctures and hyperelliptic mapping class groups are linear. In particular, the mapping class group of a closed orientable surface of genus $2$ is linear.


Intrinsic Equations For A Relaxed Elastic Line On An Oriented Hypersurface In The Minkowski Space R^N_1, Nevi̇n Gürbüz, Ali̇ Görgülü Jan 2000

Intrinsic Equations For A Relaxed Elastic Line On An Oriented Hypersurface In The Minkowski Space R^N_1, Nevi̇n Gürbüz, Ali̇ Görgülü

Turkish Journal of Mathematics

We gived the intrinsic equations for a relaxed elastic line on an oriented surface in ${\Bbb {R}}_1^3$ ([1],[2]). In this paper, we derived the intrinsic equations for a relaxed elastic line on an oriented time-like hypersurface and space-like hypersurface in the Minkowski space ${\Bbb {R}}_1^n$ and gived additional results about relaxed elastic lines on various timelike and spacelike hypersurface in the Minkowski space ${\Bbb {R}}_1^n$.


Asymptotic Behavior Of The Zero Solutions To Generalized Pipe And Rotating Shaft Equations, Ayfer Kurt Jan 2000

Asymptotic Behavior Of The Zero Solutions To Generalized Pipe And Rotating Shaft Equations, Ayfer Kurt

Turkish Journal of Mathematics

A non-autonomous partial differential equation describing the dynamics of a uniform pipe and a system describing the dynamics of a rotating shaft are considered.Sufficient conditions for the global asymptotic stability of the zero solution of the boundary value problem for the differential equation and the system under consideration are established by using the Lyapunov function technique.


Efficient Presentations For Some Direct Products Of Groups, Bi̇lal Vatansever, David M. Gill Jan 2000

Efficient Presentations For Some Direct Products Of Groups, Bi̇lal Vatansever, David M. Gill

Turkish Journal of Mathematics

In this paper we give efficient presentations for $A_4\times D_n$, where n is odd number, or n is even number and (n,3)=1. We also give efficient presentations for $A_5\times D_n$ where n is an even or odd number.


Zeros Of \Zeta^{''}(S) & \Zeta^{'''}(S) In \Sigma< 1/2, Cem Yalçin Yildirim Jan 2000

Zeros Of \Zeta^{''}(S) & \Zeta^{'''}(S) In \Sigma< 1/2, Cem Yalçin Yildirim

Turkish Journal of Mathematics

There is only one pair of non-real zeros of $\zeta^{''}(s)$, and of $\zeta^{'''}(s)$, in the left half-plane. The Riemann Hypothesis implies that $\zeta''(s)$ and $\zeta'''(s)$ have no zeros in the strip $0 \leq \Re\,s < {1\over 2} $.


Some Results On Derivation Groups, Murat Alp Jan 2000

Some Results On Derivation Groups, Murat Alp

Turkish Journal of Mathematics

In this paper we describe a share package XMOD of functions for computing with finite, permutation crossed modules, their morphisms and derivations; cat$^1$-groups, their morphisms and their sections, written using the GAP \cite{GAP} group theory programming language. We also give some mathematical results for derivations. These results are suggested by the output produced by the XMOD package.


A Generalized Trapezoid Inequality For Functions Of Bounded Variation, P. Cerone, S. S. Dragomir, C. E. M. Pearce Jan 2000

A Generalized Trapezoid Inequality For Functions Of Bounded Variation, P. Cerone, S. S. Dragomir, C. E. M. Pearce

Turkish Journal of Mathematics

We establish a generalization of a recent trapezoid inequality for functions of bounded variation. A number of special cases are considered. Applications are made to quadrature formulae, probability theory, special means and the estimation of the beta function.


Some Commutativity Results For S -Unital Rings, Moharram A. Khan Jan 2000

Some Commutativity Results For S -Unital Rings, Moharram A. Khan

Turkish Journal of Mathematics

In the present paper, it is shown that if $R$ is a left ( resp. right) $s$-unital ring satisfying $[f(y^mx^ry^s) \pm x^ty, x] = 0$ (resp. $[f(y^mx^ry^s) \pm yx^t, x] = 0),$ where $m, r, s, t$ are fixed non-negative integers and $f(\lambda)$ is a polynomial in ${\lambda}^2{\bf Z}[\lambda],$ then $R$ is commutative. Commutativity of $R$ has also been investigated under different sets of constraints on integral exponents.


Some Graph Type Hypersurfaces In A Semi-Euclidean Space, Ikawa Toshihiko, Honda Kyoko Jan 2000

Some Graph Type Hypersurfaces In A Semi-Euclidean Space, Ikawa Toshihiko, Honda Kyoko

Turkish Journal of Mathematics

We consider some graph type hypersurfaces in a semi-Euclidean space $\Bbb R^{n+1}_{q}$ and give conditions of the dimension $n+1$ and the index $q$ when a hypersurface is lightlike, totally geodesic and minimal.


Conjugacy Classes Of Elliptic Elements In The Picard Group, Ni̇hal Yilmaz, İsmai̇l Naci̇ Cangül Jan 2000

Conjugacy Classes Of Elliptic Elements In The Picard Group, Ni̇hal Yilmaz, İsmai̇l Naci̇ Cangül

Turkish Journal of Mathematics

The Picard group $\mathbf{P}$ is a discrete subgroup of $PSL(2,\Bbb{C})$ with Gaussian integer coefficients. Here it is shown that the total number of conjugacy classes of elliptic elements of order 2 and 3 in $\mathbf{P}$, which is given as seven by B. Fine $\left[ 3\right] $, can actually be reduced to four and using this, the conditions for the maximal Fuchsian subgroups of $\mathbf{P}$ to have elliptic elements of orders 2 and 3 are found.