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Articles 22621 - 22650 of 27436

Full-Text Articles in Physical Sciences and Mathematics

Permutational Labeling Of Constant Weight Gray Codes., Inessa Levi Jan 2002

Permutational Labeling Of Constant Weight Gray Codes., Inessa Levi

Faculty Bibliography

We prove that for positive integers n and r satisfying 1 < r < n, with the single exception of n = 4 and r = 2, there exists a constant weight Gray code of r-sets of Xn = {1,2,... ,n} that admits an orthogonal labelling by distinct partitions, with each subsequent partition obtained from the previous one by an application of a permutation of the underlying set. Specifically, an r-set A and a partition •K of Xn are said to be orthogonal if every class of n meets A in exactly one element. We prove that for all n and r as stated, and i = 1,2,..., I J taken modulo [ J, there exists a list Ai, A2,..., A(n\ of the distinct r-sets of Xn with \A\ n Aj+1| = r - 1 and a list of distinct partitions TTI, 7T2,..., irin\ such that TTJ is orthogonal to both Ai and Ai+i, and 7Tj+i = TTiAj for a suitable permutation A* of Xn.

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The Continuum Problem, John Stillwell Jan 2002

The Continuum Problem, John Stillwell

Mathematics

No abstract provided.

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Applications Of Graph Theory To Separability, Stephen Young Jan 2002

Applications Of Graph Theory To Separability, Stephen Young

Mathematical Sciences Technical Reports (MSTR)

Let S be a surface with a triangular tiling T. Let R be a reflection a side of one of the triangles; so that R is an orientation reversing isometry of the surface. Define M = {s in S |S : Rs = s}. We then say that the surface S separates along the reflection R if S-R has two components. This paper considers the applications of graph theoretic methods to determining whether a reflection is separating or not and compares the algorithmic efficiency of these methods to the current known methods.

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On Size Mappings, W. J. Charatonik, Alicja Samulewicz Jan 2002

On Size Mappings, W. J. Charatonik, Alicja Samulewicz

Mathematics and Statistics Faculty Research & Creative Works

A real-valued mapping r from the hyperspace of all compact subsets of a givenmetric space X is called a size mapping if r({x}) = 0 for x ∈ X and r(A) ≤ r(B) if a ⊂ B. We investigate what continua admit an open or a monotone size mapping. Special attention is paid to the diameter mappings.

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On Quadrature Rules Associated With Appell Polynomials, Gabriella Bretti, Matthew He, Paolo E. Ricci Jan 2002

On Quadrature Rules Associated With Appell Polynomials, Gabriella Bretti, Matthew He, Paolo E. Ricci

Mathematics Faculty Articles

A quadrature rule using Appell polynomials and generalizing both the Euler-MacLaurin quadrature formula and a similar quadrature rule, obtained in Bretti et al [15], which makes use of Euler (instead of Bernoulli) numbers and even (instead of odd) derivatives of the given function at the extrema of the considered interval, is derived. An expression of the remainder term and a numerical example are also enclosed.

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Accuracy, Resolution And Stability Properties Of A Modified Chebyshev Method, Jodi Mead, Rosemary A. Renaut Jan 2002

Accuracy, Resolution And Stability Properties Of A Modified Chebyshev Method, Jodi Mead, Rosemary A. Renaut

Mathematics Faculty Publications and Presentations

While the Chebyshev pseudospectral method provides a spectrally accurate method, integration of partial differential equations with spatial derivatives of order M requires time steps of approximately O(N−2M) for stable explicit solvers. Theoretically, time steps may be increased to O(N−M) with the use of a parameter, α-dependent mapped method introduced by Kosloff and Tal-Ezer [ J. Comput. Phys., 104 (1993), pp. 457–469]. Our analysis focuses on the utilization of this method for reasonable practical choices for N, namely N ≲ 30, as may be needed for two- or three dimensional modeling. Results presented …

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Laplace Transform Of Spherical Bessel Functions, Andrei Ludu Jan 2002

Laplace Transform Of Spherical Bessel Functions, Andrei Ludu

Andrei Ludu

No abstract provided.

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The Effects Of Item Parceling On Goodness-Of-Fit And Parameter Estimate Bias In Structural Equation Modeling, Deborah L. Bandalos Jan 2002

The Effects Of Item Parceling On Goodness-Of-Fit And Parameter Estimate Bias In Structural Equation Modeling, Deborah L. Bandalos

Deborah L Bandalos

No abstract provided.

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On The Approximation Properties Of Partial Sums Of Trigonometric Fourier Series, Ushangi Goginava Jan 2002

On The Approximation Properties Of Partial Sums Of Trigonometric Fourier Series, Ushangi Goginava

Ushangi Goginava

No abstract provided.

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On The Approximation Properties Of Cesàro Means Of Negative Order Of Walsh-Fourier Series, Ushangi Goginava Jan 2002

On The Approximation Properties Of Cesàro Means Of Negative Order Of Walsh-Fourier Series, Ushangi Goginava

Ushangi Goginava

No abstract provided.

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On Thickness And Packing Density For Knots And Links, Robert Kusner Jan 2002

On Thickness And Packing Density For Knots And Links, Robert Kusner

Robert Kusner

We describe some problems, observations, and conjectures concerning density of the hexagonal packing of unit disks in R2.thickness and packing density of knots and links in S3 and R3. We prove the thickness of a nontrivial knot or link in S3 is no more than 4 , the thickness of a Hopf link. We also give arguments and evidence supporting the conjecture that the packing density of thick links in R3 or S3 is generally less than √12 , the density of the hexagonal packing of unit disks in R2.

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Discrete Nonlinear Model With Substrate Feedback, P. G. Kevrekidis, B. A. Malomed, A. R. Bishop Jan 2002

Discrete Nonlinear Model With Substrate Feedback, P. G. Kevrekidis, B. A. Malomed, A. R. Bishop

Panos Kevrekidis

We consider a prototypical model in which a nonlinear field (continuum or discrete) evolves on a flexible substrate which feeds back to the evolution of the main field. We identify the underlying physics and potential applications of such a model and examine its simplest one-dimensional Hamiltonian form, which turns out to be a modified Frenkel-Kontorova model coupled to an extra linear equation. We find static kink solutions and study their stability, and then examine moving kinks (the continuum limit of the model is studied too). We observe how the substrate effectively renormalizes properties of the kinks. In particular, a nontrivial …

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On The Reducibility Of Characteristic Varieties, Tom Braden Jan 2002

On The Reducibility Of Characteristic Varieties, Tom Braden

Tom Braden

We show that some monodromies in the Morse local systems of a conically stratified perverse sheaf imply that other Morse local systems for smaller strata do not vanish. This result is then used to explain the examples of reducible characteristic varieties of Schubert varieties given by Kashiwara and Saito in type A and by Boe and Fu for the Lagrangian Grassmannian.

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A Smooth Space Of Tetrahedra, E Babson, Pe Gunnells, R Scott Jan 2002

A Smooth Space Of Tetrahedra, E Babson, Pe Gunnells, R Scott

Paul Gunnells

This is the pre-published version harvested from ArXiv. We construct a smooth symmetric compactification of the space of all labeled tetrahedra in 3.

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Nonequivalent Statistical Equilibrium Ensembles And Refined Stability Theorems For Most Probable Flows, Richard S. Ellis, Kyle Haven, Bruce Turkington Jan 2002

Nonequivalent Statistical Equilibrium Ensembles And Refined Stability Theorems For Most Probable Flows, Richard S. Ellis, Kyle Haven, Bruce Turkington

Richard S. Ellis

Statistical equilibrium models of coherent structures in two-dimensional and barotropic quasi-geostrophic turbulence are formulated using canonical and microcanonical ensembles, and the equivalence or nonequivalence of ensembles is investigated for these models. The main results show that models in which the energy and circulation invariants are treated microcanonically give richer families of equilibria than models in which they are treated canonically. For each model, a variational principle that characterizes its equilibrium states is derived by large deviation techniques. An analysis of the two different variational principles resulting from the canonical and microcanonical ensembles reveals that their equilibrium states coincide if and …

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The Brunn-Minkowski Inequality, Richard J. Gardner Jan 2002

The Brunn-Minkowski Inequality, Richard J. Gardner

Mathematics Faculty Publications

In 1978, Osserman [124] wrote an extensive survey on the isoperimetric inequality. The Brunn-Minkowski inequality can be proved in a page, yet quickly yields the classical isoperimetric inequality for important classes of subsets of Rn, and deserves to be better known. This guide explains the relationship between the Brunn-Minkowski inequality and other inequalities in geometry and analysis, and some applications.

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Form Domains And Eigenfunction Expansions For Differential Equations With Eigenparameter Dependent Boundary Conditions, Branko Ćurgus, Paul Binding Jan 2002

Form Domains And Eigenfunction Expansions For Differential Equations With Eigenparameter Dependent Boundary Conditions, Branko Ćurgus, Paul Binding

Mathematics Faculty Publications

Form domains are characterized for regular 2n-th order differential equations subject to general self-adjoint boundary conditions depending affinely on the eigenparameter. Corresponding modes of convergence for eigenfunction expansions are studied, including uniform convergence of the first n - 1 derivatives.

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Field Extensions Having The Unique Subfield Property, And G-Cogalois Extensions, Toma Albu Jan 2002

Field Extensions Having The Unique Subfield Property, And G-Cogalois Extensions, Toma Albu

Turkish Journal of Mathematics

We present a short proof, based on Cogalois Theory, of a result due to Acosta de Orozco and Vélez (1982, J. Number Theory 15, 388-405) characterizing separable simple radical field extensions with the unique subfield property, and prove that these extensions are precisely the simple G--Cogalois extensions with a cyclic Kneser group.

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Ko-Groups Of Bounded Flag Manifolds, Yusuf Ci̇van Jan 2002

Ko-Groups Of Bounded Flag Manifolds, Yusuf Ci̇van

Turkish Journal of Mathematics

We exhibit an appropriate suspension of bounded flag manifolds as a wedge sum of Thom complexes of associated complex line bundles. We use the existence of such a splitting to assist our computation of real and complex K-groups. Moreover, we compute the Sq^2-homology of bounded flag manifolds to make use of relevant Atiyah-Hirzebruch spectral sequence of KO-theory.

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\Theta-Euclidean L-Fuzzy Ideals Of Rings, Ayten Koç, Erol Balkanay Jan 2002

\Theta-Euclidean L-Fuzzy Ideals Of Rings, Ayten Koç, Erol Balkanay

Turkish Journal of Mathematics

The concept of fuzzy ideals is extended by introducing \theta -Euclidean L-fuzzy ideals in rings. In particular, some structural theorems for a \theta -Euclidean L-fuzzy ideal of R are proved.

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Left Adjoint Of Pullback Cat^1- Profinite Groups, Murat Alp Jan 2002

Left Adjoint Of Pullback Cat^1- Profinite Groups, Murat Alp

Turkish Journal of Mathematics

In this paper, we present a brief review crossed modules \cite{whitehead}, cat^1-groups \cite{loday}, profinite crossed modules \cite{kortim}, cat^1-profinite groups \cite{kortim}, pullback profinite crossed modules \cite{kortim} and also the pullback cat^1- profinite groups \cite{hind}. We prove that the pulback cat^1-profinite group has a left adjoint which is the induced cat^1-group.

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New Tensor Norms And Operator Ideals Associated To Interpolation Spaces Between Sequence Spaces, G. Castaneda, J. A. Lopez Molina, M. J. Rivera Jan 2002

New Tensor Norms And Operator Ideals Associated To Interpolation Spaces Between Sequence Spaces, G. Castaneda, J. A. Lopez Molina, M. J. Rivera

Turkish Journal of Mathematics

We introduce a wide class of tensor norms g_{\lambda,\rho} which are defined with the help of interpolation spaces between perfect sequence spaces defined by a general parameter real interpolation method. We also characterize the associated \lambda_{\rho}-nuclear and \lambda_{\rho}-integral operators.

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Characterizations Of Artinian And Noetherian Gamma-Rings In Terms Of Fuzzy Ideals, Mehmet Ali̇ Öztürk, Mustafa Uçkun, Young Bae Jun Jan 2002

Characterizations Of Artinian And Noetherian Gamma-Rings In Terms Of Fuzzy Ideals, Mehmet Ali̇ Öztürk, Mustafa Uçkun, Young Bae Jun

Turkish Journal of Mathematics

Using fuzzy ideals, characterizations of Noetherian \Gamma-rings are given, and a condition for a \Gamma-ring to be Artinian is also given.

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On Non-Existence Of Korovkin's Theorem In The Space Of L_{P}-Locally Integrable Functions, A. D. Gadjiev, Ertan İbi̇kli̇ Jan 2002

On Non-Existence Of Korovkin's Theorem In The Space Of L_{P}-Locally Integrable Functions, A. D. Gadjiev, Ertan İbi̇kli̇

Turkish Journal of Mathematics

It is shown that a Korovkin-type theorem does not hold in the weighted space of L_{p}-locally integrable functions on the whole real axis.

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Deformation Inequivalent Complex Conjugated Complex Structures And Applications, Viatcheslav Kharlamov, Viktor Kulikov Jan 2002

Deformation Inequivalent Complex Conjugated Complex Structures And Applications, Viatcheslav Kharlamov, Viktor Kulikov

Turkish Journal of Mathematics

We start from a short summary of our principal result from [KK]: an example of a complex algebraic surface which is not deformation equivalent to its complex conjugate and which, moreover, has no homeomorphisms reversing the canonical class. Then, we generalize this result to higher dimensions and construct several series of higher dimensional compact complex manifolds having no homeomorphisms reversing the canonical class. After that, we resume and broaden the applications given in [KK] and [KK2], in particular, as a new application, we propose examples of (deformation) non equivalent symplectic structures with opposite canonical classes.

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Combinatorial Patchworking Of Real Pseudo-Holomorphic Curves, Ilia Itenberg, Eugenii Shustin Jan 2002

Combinatorial Patchworking Of Real Pseudo-Holomorphic Curves, Ilia Itenberg, Eugenii Shustin

Turkish Journal of Mathematics

The Viro method of construction of real algebraic varieties with prescribed topology uses convex subdivisions of Newton polyhedra. We show that in the case of arbitrary (not necessarily convex) subdivisions of polygons corresponding to C P^2 and rational ruled surfaces \Sigma_a, a \geq 0 the Viro method produces pseudo-holomorphic curves. The version of the Viro method discussed in the paper also gives a possibility to construct singular pseudo-holomorphic curves by gluing singular algebraic curves whose collections of singularities do not permit to glue these curves in the framework of the standard Viro method. As an application, we construct a series …

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On 1-Point Gromov-Witten Invariants Of The Hilbert Schemes Of Points On Surfaces, Wei-Ping Li, Zhenbo Qin Jan 2002

On 1-Point Gromov-Witten Invariants Of The Hilbert Schemes Of Points On Surfaces, Wei-Ping Li, Zhenbo Qin

Turkish Journal of Mathematics

We compute certain 1-point genus-0 Gromov-Witten invariants of the Hilbert scheme of points on a simply-connected smooth projective surface.

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Evidence For A Conjecture Of Pandharipande, Jim Bryan Jan 2002

Evidence For A Conjecture Of Pandharipande, Jim Bryan

Turkish Journal of Mathematics

In his paper ``Hodge integrals and degenerate contributions'', Pandharipande studied the relationship between the enumerative geometry of certain 3-folds and the Gromov-Witten invariants. In some good cases, enumerative invariants (which are manifestly integers) can be expressed as a rational combination of Gromov-Witten invariants. Pandharipande speculated that the same combination of invariants should yield integers even when they do not have any enumerative significance on the 3-fold. In the case when the 3-fold is the product of a complex surface and an elliptic curve, Pandharipande has computed this combination of invariants on the 3-fold in terms of the Gromov-Witten invariants of …

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Minimality Of Certain Normal Connected Sums, Tian-Jun Li, Andras I. Stipsicz Jan 2002

Minimality Of Certain Normal Connected Sums, Tian-Jun Li, Andras I. Stipsicz

Turkish Journal of Mathematics

We show that the normal connected sum of two minimal symplectic 4-manifolds (neither of them rational or ruled) is a minimal symplectic 4-manifold. In the proof we use a symplectic sum formula for Gromov-Witten invariants.

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Variations On Fintushel-Stern Knot Surgery On 4-Manifolds, Selman Akbulut Jan 2002

Variations On Fintushel-Stern Knot Surgery On 4-Manifolds, Selman Akbulut

Turkish Journal of Mathematics

We discuss some consequences Fintushel-Stern `knot surgery' operation coming from its handlebody description. We give some generalizations of this operation and give a counterexample to their conjecture.

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