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Articles 23791 - 23820 of 27413

Full-Text Articles in Physical Sciences and Mathematics

The Object And The Study Of Mathematics, Pinar Karaca Nov 1997

The Object And The Study Of Mathematics, Pinar Karaca

Humanistic Mathematics Network Journal

No abstract provided.


John Dewey, The Math And Science Standards, And The Workplace, Bernard A. Fleishman Nov 1997

John Dewey, The Math And Science Standards, And The Workplace, Bernard A. Fleishman

Humanistic Mathematics Network Journal

No abstract provided.


Poems, David L. Finn Nov 1997

Poems, David L. Finn

Humanistic Mathematics Network Journal

No abstract provided.


Inspiration In England, Mary Mcdermott Nov 1997

Inspiration In England, Mary Mcdermott

Humanistic Mathematics Network Journal

No abstract provided.


A Course In Mathematical Ethics, Robert P. Webber Nov 1997

A Course In Mathematical Ethics, Robert P. Webber

Humanistic Mathematics Network Journal

No abstract provided.


Book Review: Nexus: Architecture And Mathematics, Edited By Kim Williams, Joseph Malkevitch Nov 1997

Book Review: Nexus: Architecture And Mathematics, Edited By Kim Williams, Joseph Malkevitch

Humanistic Mathematics Network Journal

No abstract provided.


Book Review: Ethnomathematics--Challenging Eurocentrism Inmathematics Education, Edited Byarthur B. Powell And Marilyn Frankenstein, Karen Dee Michalowicz Nov 1997

Book Review: Ethnomathematics--Challenging Eurocentrism Inmathematics Education, Edited Byarthur B. Powell And Marilyn Frankenstein, Karen Dee Michalowicz

Humanistic Mathematics Network Journal

No abstract provided.


Borsuk-Ulam Implies Brouwer: A Direct Construction, Francis E. Su Nov 1997

Borsuk-Ulam Implies Brouwer: A Direct Construction, Francis E. Su

All HMC Faculty Publications and Research

No abstract provided in this article.


A Simple Formula For Pi, V. Adamchik, Stan Wagon Oct 1997

A Simple Formula For Pi, V. Adamchik, Stan Wagon

Stan Wagon, Retired

No abstract provided.


Orbifolds With Lower Ricci Curvature Bounds, Joseph E. Borzellino Oct 1997

Orbifolds With Lower Ricci Curvature Bounds, Joseph E. Borzellino

Mathematics

We show that the first betti number of a compact Riemannian orbifold with Ricci curvature and diameter is bounded above by a constant , depending only on dimension, curvature and diameter. In the case when the orbifold has nonnegative Ricci curvature, we show that the is bounded above by the dimension , and that if, in addition, , then is a flat torus .


A Sign-Changing Solution For A Superlinear Dirichlet Problem, Alfonso Castro, Jorge Cossio, John M. Neuberger Oct 1997

A Sign-Changing Solution For A Superlinear Dirichlet Problem, Alfonso Castro, Jorge Cossio, John M. Neuberger

All HMC Faculty Publications and Research

We show that a superlinear boundary value problem has at least three nontrivial solutions. A pair are of one sign (positive and negative, respectively), and the third solution changes sign exactly once. The critical level of the sign-changing solution is bounded below by the sum of the two lesser levels of the one-sign solutions. If nondegenerate, the one sign solutions are of Morse index 1 and the signchanging solution has Morse index 2. Our results extend and complement those of Z.Q. Wang [12].


A Unifying Construction For Difference Sets, James A. Davis, Jonathan Jedwab Oct 1997

A Unifying Construction For Difference Sets, James A. Davis, Jonathan Jedwab

Department of Math & Statistics Faculty Publications

We present a recursive construction for difference sets which unifies the Hadamard, McFarland, and Spence parameter families and deals with all abelian groups known to contain such difference sets. The construction yields a new family of difference sets with parameters (v, k, λ,n)=(22d+4(22d+2−1)/3, 22d+1(22d+3+1)/3, 22d+1(22d+1+1)/3, 24d+2) for d⩾0. The construction establishes that a McFarland difference set exists in an abelian group of order 22 …


Computational Geometry Column 32, Joseph O'Rourke Oct 1997

Computational Geometry Column 32, Joseph O'Rourke

Computer Science: Faculty Publications

The proof of Dey's new k-set bound is illustrated.


Compactness-Like Operator Properties Preserved By Complex Interpolation, Karen Saxe Sep 1997

Compactness-Like Operator Properties Preserved By Complex Interpolation, Karen Saxe

Karen Saxe

No abstract provided.


The Convergence Of The Solutions Of The Navier-Stokes Equations To That Of The Euler Equations, R. Temam, X. Wang Sep 1997

The Convergence Of The Solutions Of The Navier-Stokes Equations To That Of The Euler Equations, R. Temam, X. Wang

Mathematics and Statistics Faculty Research & Creative Works

In this article, we establish partial results concerning the convergence of the solutions of the Navier-Stokes equations to that of the Euler equations. Convergence is proved in space dimension two under a physically reasonable assumption, namely that the gradient of the pressure remains bounded at the boundary as the Reynolds number converges to infinity.


Attractors For Nonautonomous Nonhomogeneous Navier-Stokes Equations, A. Miranville, X. Wang Sep 1997

Attractors For Nonautonomous Nonhomogeneous Navier-Stokes Equations, A. Miranville, X. Wang

Mathematics and Statistics Faculty Research & Creative Works

In this paper our aim is to derive an upper bound on the dimension of the attractor of the family of processes associated to the Navier-Stokes equations with nonhomogeneous boundary conditions depending on time. We consider two-dimensional flows with prescribed quasiperiodic (in time) tangential velocity at the boundary, and obtain an upper bound which is polynomial with respect to the viscosity.


Preservation Of The Range Under Perturbations Of An Operator, Branko Ćurgus, Branko Najman Sep 1997

Preservation Of The Range Under Perturbations Of An Operator, Branko Ćurgus, Branko Najman

Mathematics Faculty Publications

A sufficient condition for the stability of the range of a positive operator in a Hilbert space is given. As a consequence, we get a class of additive perturbations which preserve regularity of the critical point 0 of a positive operator in a Krein space.


Legendrian Circular Helix Links, Lisa Traynor Sep 1997

Legendrian Circular Helix Links, Lisa Traynor

Mathematics Faculty Research and Scholarship

Examples are given of legendrian links in the manifold of cooriented contact elements of the plane, or equivalently, in the 1-jet space of the circle which are not equivalent via an isotopy of contact diffeomorphisms. These examples have generalizations to linked legendrian spheres in contact manifolds diffeomorphic to R-n x Sn-1. These links are distinguished by applying the theory of generating functions to contact manifolds.


On The Product Of Two Generalized Derivations, Mohamed Barraa, Steen Pedersen Sep 1997

On The Product Of Two Generalized Derivations, Mohamed Barraa, Steen Pedersen

Mathematics and Statistics Faculty Publications

Two elements A and B in a ring R determine a generalized derivation deltaA,B on R by setting δA,B(X) = AX - XA for any X in R. We characterize when the product δC,DδA,B is a generalized derivation in the cases when the ring R is the algebra of all bounded operators on a Banach space epsilon, and when R is a C*-algebra U. We use the se characterizations to compute the commutant of the range of δA,B.


Asymptotics Of Zeros Of Relativistic Hermite Polynomials, Matthew He, K. Pan, Paolo E. Ricci Sep 1997

Asymptotics Of Zeros Of Relativistic Hermite Polynomials, Matthew He, K. Pan, Paolo E. Ricci

Mathematics Faculty Articles

The relativistic Hermite polynomial (RHP) is a class of orthogonal polynomials associated with varying weights. We study the asymptotics of the zeros of the RHP when both degree $n$ of polynomials and relativistic parameter $N$ approach infinity.


Complexity And Decomposability Of Relations, Martin Zwick Sep 1997

Complexity And Decomposability Of Relations, Martin Zwick

Systems Science Faculty Publications and Presentations

A discrete multivariate relation, defined set-theoretically, is a subset of a cartesian product of sets which specify the possible values of a number of variables. Where three or more variables are involved, the highest order relation, namely the relation between all the variables, may or may not be decomposable without loss into sets of lower order relations which involve subsets of the variables. In a completely parallel manner, the highest order relation defined information-theoretically, namely the joint probability distribution involving all the variables, may or may not be decomposed without loss into lower-order distributions involving subsets of the variables. Decomposability …


Pompeiu Problem And Analogues Of The Weiner-Tauberian Theorem For Certain Homogeneous Spaces., Rama Rawat Dr. Aug 1997

Pompeiu Problem And Analogues Of The Weiner-Tauberian Theorem For Certain Homogeneous Spaces., Rama Rawat Dr.

Doctoral Theses

Let G be a connected locally compact unimodular group acting transitively on a locally compact space X. For a function f on X and g € G, define of by 9f(x) = fA 9.a), a € X. One of the recurring themes in analysis is the question of when a function f in a given function space F(X) will have property that Span{gf : g € G} is dense in F(X). If X = R and G = R, the celebrated Wiener-Tauberian theorem answers this question completely for the space L1(R): The span of the translates of fE L1(R) is …


Invariant Subspaces And Hyper-Reflexivity For Free Semigroup Algebras, Kenneth R. Davidson, David R. Pitts Aug 1997

Invariant Subspaces And Hyper-Reflexivity For Free Semigroup Algebras, Kenneth R. Davidson, David R. Pitts

Department of Mathematics: Faculty Publications

In this paper, we obtain a complete description of the invariant subspace structure of an interesting new class of algebras which we call free semigroup algebras. This enables us to prove that they are reflexive, and moreover to obtain a quantitative measure of the distance to these algebras in terms of the invariant subspaces. Such algebras are called hyper-reflexive. This property is very strong, but it has been established in only a very few cases. Moreover the prototypes of this class of algebras are the natural candidate for a non-commutative analytic Toeplitz algebra on n variables. The case we make …


Oval Intersections In Tilings On Surfaces, Dennis A. Schmidt Aug 1997

Oval Intersections In Tilings On Surfaces, Dennis A. Schmidt

Mathematical Sciences Technical Reports (MSTR)

A tiling is a covering by polygons, without gaps or overlapping, of a compact, orientable surface. We are particularly interested in tilings by triangles that generate a large symmetry group of the surface. An oval of the tiling is a simple, closed curve that is a union of edges of the tiling. We investigate the number of points of intersection of two ovals. We have found that the number of intersections is bounded when the subgroup of orientation preserving symmetries is abelian. However, there is no upper bound on the number of intersections in the non-abelian case.


Counting Ovals On A Symmetric Riemann Surface, Sean A. Broughton Aug 1997

Counting Ovals On A Symmetric Riemann Surface, Sean A. Broughton

Mathematical Sciences Technical Reports (MSTR)

Let S be a compact Riemann surface without boundary. A symmetry of S is an anti-conformal, involutary automorphism. Its fixed point set is a disjoint union of circles, each of which is called an oval. A method is presented for counting the ovals of a symmetry when S admits a large group G of automorphisms. The method involves only calculations in G, based on the geometric description of S/G, and the knowledge of the action of the symmetry on G.


Pseudocontinuations And The Backward Shift, Alexandru Aleman, Stefan Richter, William T. Ross Aug 1997

Pseudocontinuations And The Backward Shift, Alexandru Aleman, Stefan Richter, William T. Ross

Department of Math & Statistics Technical Report Series

In this paper, we will examine the backward shift operator Lƒ = (ƒ – ƒ(0))/z on certain Banach spaces of analytic functions on the open unit disk D. In particular, for a (closed) subspace M for which LM M, we wish to determine the spectrum, the point spectrum, and the approximate point spectrum of L|M. In order to do this, we will use the concept of "pseudocontinuation" of functions across the unit circle ∏.


A Generalized Mahonian Statistic On Absorption Ring Mappings, Don Rawlings Aug 1997

A Generalized Mahonian Statistic On Absorption Ring Mappings, Don Rawlings

Mathematics

Based on a coin-tossing scheme, a generalized Mahonian statistic is defined on absorption ring mappings and applied in obtaining combinatorial interpretations of the coefficient ofqjin the expansion of ∏ki=1 (1+q+q2+…+qmi). In the permutation case, the statistic coincides with one studied by Han that specializes many known Mahonian statistics.


Infinite-Dimensional Hamilton-Jacobi-Bellman Equations In Gauss-Sobolev Spaces, Pao-Liu Chow, Jose-Luis Menaldi Aug 1997

Infinite-Dimensional Hamilton-Jacobi-Bellman Equations In Gauss-Sobolev Spaces, Pao-Liu Chow, Jose-Luis Menaldi

Mathematics Faculty Research Publications

We consider the strong solution of a semi linear HJB equation associated with a stochastic optimal control in a Hilbert space H: By strong solution we mean a solution in a L2(μ,H)-Sobolev space setting. Within this framework, the present problem can be treated in a similar fashion to that of a finite-dimensional case. Of independent interest, a related linear problem with unbounded coefficient is studied and an application to the stochastic control of a reaction-diffusion equation will be given.


Hypersurfaces In R-D And The Variance Of Exit Times For Brownian Motion, Kimberly Kinateder, Patrick Mcdonald Aug 1997

Hypersurfaces In R-D And The Variance Of Exit Times For Brownian Motion, Kimberly Kinateder, Patrick Mcdonald

Mathematics and Statistics Faculty Publications

Using the first exit time for Brownian motion from a smoothly bounded domain in Euclidean space, we define two natural functionals on the space of embedded, compact, oriented, unparametrized hypersurfaces in Euclidean space. We develop explicit formulas for the first variation of each of the functionals and characterize the critical points.


Quasi-Steady Monopole And Tripole Attractors In Relaxing Vortices, Louis F. Rossi, Joseph F. Lingevitch, Andrew J. Bernoff Aug 1997

Quasi-Steady Monopole And Tripole Attractors In Relaxing Vortices, Louis F. Rossi, Joseph F. Lingevitch, Andrew J. Bernoff

All HMC Faculty Publications and Research

Using fully nonlinear simulations of the two-dimensional Navier–Stokes equations at large Reynolds number (Re), we bracket a threshold amplitude above which a perturbed Gaussian monopole will relax to a quasi-steady, rotating tripole, and below which will relax to an axisymmetric monopole. The resulting quasi-steady structures are robust to small perturbations. We propose a means of measuring the decay rate of disturbances to asymptotic vortical structures wherein streamlines and lines of constant vorticity correspond in some rotating or translating frame. These experiments support the hypothesis that small or moderate deviations from asymptotic structures decay through inviscid and viscous mixing.