Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Mathematics

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 22981 - 23010 of 27431

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.

Go to article

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.

Go to article

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.

Go to article

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.

Go to article

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.

Go to article

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)).

Go to article

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] …

Go to article

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.

Go to article

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.

Go to article

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 …

Go to article

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 …

Go to article

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.

Go to article

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

Go to article

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.

Go to article

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 …

Go to article

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.

Go to article

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.

Go to article

Efficient Algorithms For Graphs With Few P-4’S, Luitpold Babel, Ton Kloks, Jan Kratochvíl, Dieter Kratsch, Kaiko Müller, Stephan Olariu Jan 2001

Efficient Algorithms For Graphs With Few P-4’S, Luitpold Babel, Ton Kloks, Jan Kratochvíl, Dieter Kratsch, Kaiko Müller, Stephan Olariu

Computer Science Faculty Publications

We show that a large variety of NP-complete problems can be solved efficiently for graphs with 'few' P4's. We consider domination problems (domination, total domination, independent domination. connected domination and dominating clique), the Steiner tree problem, the vertex ranking problem, the pathwidth problem, the path cover number problem, the hamiltonian circuit problem, the list coloring problem and the precoloring extension problem. We show that all these problems can be solved in linear time for the class of (q,q - 4)-graphs, for every fixed q. These are graphs for which no set of at most q. vertices induces more …

Go to article

Algorithms For Operations On Probability Distributions In A Computer Algebra System, Diane Lynn Evans Jan 2001

Algorithms For Operations On Probability Distributions In A Computer Algebra System, Diane Lynn Evans

Dissertations, Theses, and Masters Projects

In mathematics and statistics, the desire to eliminate mathematical tedium and facilitate exploration has lead to computer algebra systems. These computer algebra systems allow students and researchers to perform more of their work at a conceptual level. The design of generic algorithms for tedious computations allows modelers to push current modeling boundaries outward more quickly.;Probability theory, with its many theorems and symbolic manipulations of random variables is a discipline in which automation of certain processes is highly practical, functional, and efficient. There are many existing statistical software packages, such as SPSS, SAS, and S-Plus, that have numeric tools for statistical …

Go to article

A 4-Dimensional 1-Lcc Shrinking Theorem, Mladen Bestvina, Robert J. Daverman, Gerard A. Venema Jan 2001

A 4-Dimensional 1-Lcc Shrinking Theorem, Mladen Bestvina, Robert J. Daverman, Gerard A. Venema

University Faculty Publications and Creative Works

This paper contains several shrinking theorems for decompositions of 4-dimensional manifolds. Let f : M → X be a closed, cell-like mapping of a 4-manifold M onto a metric space X and let Y be a closed subset of X such that X - Y is a 4-manifold and Y is locally simply co-connected in X. The main result states that f can be approximated by homeomorphisms if Y is a 1-dimensional ANR. The techniques of the proof also show that f can be approximated by homeomorphisms in case Y is an arbitrary 0-dimensional closed subset. Combining the two results …

Go to article

Measure Zero Sets With Non-Measurable Sum, Krzysztof Ciesielski Jan 2001

Measure Zero Sets With Non-Measurable Sum, Krzysztof Ciesielski

Faculty & Staff Scholarship

For any subset C of R there is a subset A of C such that A+A has inner measure zero and outer measure the same as C+C. Also, there is a subset A of the Cantor middle third set such that A+A is Bernstein in [0,2]. On the other hand there is a perfect set C such that C+C is an interval I and there is no subset A of C with A+A Bernstein in I.

Go to article

Discrete-Time Approximations Of Stochastic Differential Systems With Memory, Yaozhong Hu, Salah-Eldin A. Mohammed, Feng Yan Jan 2001

Discrete-Time Approximations Of Stochastic Differential Systems With Memory, Yaozhong Hu, Salah-Eldin A. Mohammed, Feng Yan

Articles and Preprints

In this paper, we develop two discrete-time strong approximation schemes for solving stochastic differential systems with memory: strong Euler-Maruyama schemes for stochastic delay differential equations (SDDE's) and stochastic functional differential equations (SFDE's) with continuous memory, and a strong Milstein scheme for SDDE's. The convergence orders of the Euler-Maruyama and Milstein schemes are 0.5 and 1 respectively. In order to establish the Milstein scheme, we prove an infinite-dimensional Itô formula for "tame" functions acting on the segment process of the solution of an SDDE. It is interesting to note that the presence of the memory in the SDDE requires the use …

Go to article

Using Generalized Linear Models With A Mixed Random Component To Analyze Count Data, Jungah Jung Jan 2001

Using Generalized Linear Models With A Mixed Random Component To Analyze Count Data, Jungah Jung

Electronic Theses and Dissertations

Many discrete response variables have counts as possible outcomes. Poisson regression has been recognized as an important tool for analyzing count data. This technique includes the simple Poisson generalized linear model and mixtures of independent Poisson models as special cases. Generalized linear models have been found useful in many statistical analysis. Count data analyzed under such models often exhibit overdispersion. In many practical circumstances the restriction that the mean and variance are equal is not realistic. Especially, when there is overdispersion in the data, a conditional negative binomial mixed model, given some random effects, could be an attractive alternative. This …

Go to article

An Almost Deep Degree, Peter Cholak, Marcia Groszek, Theodore Slaman Jan 2001

An Almost Deep Degree, Peter Cholak, Marcia Groszek, Theodore Slaman

Dartmouth Scholarship

We show there is a non-recursive r.e. set A such that if W is any low r.e. set. then the join W ⊕ A is also low. That is. A is “almost deep”. This answers a question of Joekusch. The almost deep degrees form an definable ideal in the r.e. degrees (with jump.)

Go to article

Eddy Structures Induced Within A Wedge By A Honing Circular Arc, C. P. Hills Jan 2001

Eddy Structures Induced Within A Wedge By A Honing Circular Arc, C. P. Hills

Articles

In this paper we outline an expeditious numerical procedure to calculate the Stokes flow in a corner due to the rotation of a scraping circular boundary. The method is also applicable to other wedge geometries. We employ a collocation technique utilising a basis of eddy (similarity) functions introduced by Moffatt (1964) that allows us to satisfy automatically the governing equations for the streamfunction and all the boundary conditions on the surface of the wedge. The circular honing problem thereby becomes one-dimensional requiring only the satisfaction of conditions on the circular boundary. The advantage of using the Moffatt eddy functions as …

Go to article

Gravitational Descendants And The Moduli Space Of Higher Spin Curves, Tyler J. Jarvis, Takashi Kimura, Arkady Vaintrob Jan 2001

Gravitational Descendants And The Moduli Space Of Higher Spin Curves, Tyler J. Jarvis, Takashi Kimura, Arkady Vaintrob

Faculty Publications

The purpose of this note is introduce a new axiom (called the Descent Axiom) in the theory of r-spin cohomological field theories. This axiom explains the origin of gravitational descendants in this theory. Furthermore, the Descent Axiom immediately implies the Vanishing Axiom, explicating the latter (which has no a priori analog in the theory of Gromov-Witten invariants), in terms of the multiplicativity of the virtual class. We prove that the Descent Axiom holds in the convex case, and consequently in genus zero.

Go to article

Asymptotic Inference In Censored Regression Models Revisited, Chihwa Kao Jan 2001

Asymptotic Inference In Censored Regression Models Revisited, Chihwa Kao

Center for Policy Research

This paper establishes that regressors in the models with censored dependent variables need not be bounded for the standard asymptotic results to apply. Thus, regressors that grow monotonically with the observation index may be acceptable. It also purports to provide an upper bound on the rate at which regressors may grow.

Go to article

Some New Approaches To Formulate And Estimate Friction-Bernoulli Jump Diffusion And Friction-Garch, Chihwa Kao Jan 2001

Some New Approaches To Formulate And Estimate Friction-Bernoulli Jump Diffusion And Friction-Garch, Chihwa Kao

Center for Policy Research

In this paper we propose a friction model with a Beroulli jump diffusion and a friction with GARCH to examine the exchange rates movements in Taiwan. The proposed model resolves the estimation problem associated with the stepwise movements of observed exchange rates. The specification maintains the desirable economic properties associated with movements in exchange rate returns and is empirically tractable. The AIC apparently favors the model based on Friction-GARCH model.

Go to article

On Marczewski-Burstin Representations Of Certain Algebras Of Sets, Krzysztof Ciesielski Jan 2001

On Marczewski-Burstin Representations Of Certain Algebras Of Sets, Krzysztof Ciesielski

Faculty & Staff Scholarship

We show that the Generalized Continuum Hypothesis GCH (its appropriate part) implies that many natural algebras on R, including the algebra B of Borel sets and the interval algebra S, are outer Marczewski-Burstin representable by families of non-Borel sets. Also we construct, assuming again an appropriate part of GCH, that there are algebras on R which are not MB-representable. We prove that some algebras (including B and S) are not inner MB-representable. We give examples of algebras which are inner and outer MB-representable, or are inner but not outer MB-representable.

Go to article

Measure Zero Sets Whose Algebraic Sum Is Non-Measurable, Krzysztof Ciesielski Jan 2001

Measure Zero Sets Whose Algebraic Sum Is Non-Measurable, Krzysztof Ciesielski

Faculty & Staff Scholarship

In this note we will show that for every natural number n > 0 there exists an S ⊂ [0, 1] such that its n-th algebraic sum nS = S + ··· + S is a nowhere dense measure zero set,but its n+ 1-st algebraic sum nS +S is neither measurable nor it has the Baire property. In addition,the set S will be also a Hamel base,that is,a linear base of R over Q.

Go to article

First Prev Next Last