S-定向完备偏序集范畴

给出定向完备偏序半群的定义,研究定向完备偏序半群在定向完备偏序集上的作用.探讨S-定向完备偏序集范畴的一些基本性质,并且证明以S-定向完备偏序集为对象,以S-Scott连续映射为态射的范畴是笛卡尔闭范畴.     

定向空间的way below基

文章将连续定向空间的<<-基推广到了交连续定向空间和拟连续定向空间.并给出了定向拓扑的基与(拟)<<-基的关系,以及连续定向空间<<-基与其拟<<-基、交<<-基的关系.     

复数及其在几何中的应用(續)

4.作为平面的定向直綫的对偶数。以下我們将几乎只跟定向直綫打交道,所以常略去“定向”两字。我們把定向直綫a和b間的定向角/{a,b}叫作直綫a和b間的角(参見本刊7月号P.45);把直綫l上的綫段AB的定向长叫作点A和B間的距离,記作{A,B},它是通常的长度加上一个“正”或“負”的符号,这个符号看由A到B的方向是否与     

在不可定向的流形网格曲面上计算测地距离的一般方法

不可定向的流形曲面不仅在拓扑学中占据重要的地位,在可视化和极小曲面等问题中也有很多的应用.从拓扑学的观点来看,二流形曲面的每个局部与圆盘同胚,该性质与曲面的全局可定向性无关.但在离散化的网格表示上,可定向的二流形曲面常用半边结构来表达,而不可定向的二流形曲面大多表达成若干多边形的集合,这给以可定向网格曲面为主要研究对象的数字几何处理带来很多不便.本文提出了把不可定向的二流形网格曲面上的测地距离问题转化到可定向曲面上进行处理的一般算法框架.该框架有望在不可定向的二流形网格曲面与传统数字几何处理方法之间搭起一座桥梁.为了展示该算法框架的普适性,本文将其应用于不可定向曲面上的三个重要场合,包括测地距离的求解、离散指数映射和最远点采样.     

圆周上连续自映射嵌入半流的充要条件

文[1]给出了线段上连续自映射嵌入半流的充要条件.本文找到了圆周上连续自映射嵌入半流的充要条件. 定义 f:S~1→S~1是映射,若对x_1,x_2∈S~1,当x从x_1沿逆时针方向运动到x_2时f(x)取常值或从f(x_1)沿逆(顺)时针方向运动到f(x_2),则称f保持定向(保持反定向),如果f保持定向(保持反定向)且在S~1的任一弧段上不取常值,则称f严格保持定向(严格保持反定向).     

城市交通系统道路合理定向模型及其算法

从平衡性角度出发，提出了城市交通系统道路网络的合理定向定义，给出了合理定向的网络模型和数学规划模型，进而为城市交通系统道路合理定向设计了标号算法，给出了该算法的近似比。     

定向链环的一个多项式不变量

文[1]和[2]分别给不定向链环和定向链环定义了一个多项式不变量Q和P,本文对定向链环定义了一个多项式不变量F,它完全确定了Q,部分地确定了P。     

玻璃钢定向管热力学性能研究与模拟

定向器是火箭武器系统的重要组成部分,在长期贮存过程中,受到各种应力因素和环境因素的作用,不可避免地发生老化现象,这对武器系统可靠性有着重要影响.该文以玻璃钢定向器为研究对象,进行玻璃钢单向板基本热力学性能试验,并通过试验和测量,获得定向管玻璃钢材料的基本热力学性能,含加速老化后的基本力学性能;构建玻璃钢定向器力学模型,分析其受载时的热力学特性,再建立玻璃钢定向器蠕变模型,即复合材料铺层模型和各向异性模型,在结构模型中进行计算分析,所得的计算参数为建立非金属定向管长贮性能分析的计算模型提供材料参数.     

定向可图的度偶序列

n为非负整数序列，若存在以该序列为度序列的图，则称n为可图的，特别的，若此图是一个定向图，该序列则称为是定向可图的，本提出了一个判断序列是否为定向可图的充分必要条件，并且在定理的证明过程中给出了一个在定理条件下构造所求定向图的有效算法。     

不可定向曲面上的最大亏格嵌入和最小亏格嵌入

研究了不可定向曲面上最大亏格嵌入的估计数,得到了几类图的指数级不可定向最大亏格嵌入的估计数的下界.利用电流图理论,证明了完全图K_(12s)在不可定向曲面上至少有2~(3s-1)个最小亏格嵌入;完全图K_(12s+3)在不可定向曲面上至少有2~(2s)个最小亏格嵌入;完全图K_(12s+7)在不可定向曲面上至少有2~(2s+1)个最小亏格嵌入.     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

CONTENTS OF VOLUME 30

正~~     

Instructions for contributions

正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with     

Journal of Mathematical Research with Applications Guide for Authors

正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.     

Staircase transportation problems with superadditive rewards and cumulative capacities

A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].     

Laminations minimales résiduellement à 2 bouts

Résumé On décrit toutes les feuilles des laminations minimales dont un ensemble résiduel de feuilles ont 2 bouts.      

Best approximation by downward sets with applications

We develop a theory of downward sets for a class of normed ordered spaces. We study best approximation in a normed ordered space X by elements of downward sets, and give necessary and sufficient conditions for any element of best approximation by a closed downward subset of X. We also characterize strictly downward subsets of X, and prove that a downward subset of X is strictly downward if and only if each its boundary point is Chebyshev. The results obtained are used for examination of some Chebyshev pairs （W,x）, where ∈ X and W is a closed downward subset of X     

Boundedness of multilinear operators on weighted herz type spaces

In this paper, the author establishes the boundedness of multilinear operators on weighted Herz spaces and Herz-type Hardy spaces. The author also obtains their weak estimates on endpoints. As a special case, the conclusions may lead to the weighted estimates for multilinear Calderon-Zygmund operators.     

Qualitative Analysis of Bifurcating Solutions in the Lengyel-Epstein Model

One of the most fundamental problems in theoretical biology is to explain the mechanisms by which patterns and forms are created in the＇living world. In his seminal paper ＂The Chemical Basis of Morphogenesis＂, Turing showed that a system of coupled reaction-diffusion equations can be used to describe patterns and forms in biological systems. However, the first experimental evidence to the Turing patterns was observed by De Kepper and her associates（1990） on the CIMA reaction in an open unstirred reactor, almost 40 years after Turing＇s prediction. Lengyel and Epstein characterized this famous experiment using a system of reaction-diffusion equations. The Lengyel-Epstein model is in the form as follows