K[X]^m中模的生成基及其应用

本文研究了多项式环上的素模中的生成基理论和方法。通过建立新的约化准则,得到了模中生成基的结构和机械计算方法。对于低维情形给出了素右生成基的充分必要条件。文中的方法本质地简化了传统的模中Grobner基方法。文中同时介绍了该方法在样条理论研究中的应用,并给出了一些计算例子。     

射影空间中代数曲线与超曲面的一些新的性质

发现了代数曲线的新的不变量一特征数,并得到了Pascal定理的不同于3次曲线的Cllasles定理和高次曲线中的Cayley-Bacharach定理等形式的高次推广.进一步研究了平面代数曲线的一些性质.通过定义m次Pascal超曲面,将Pascal定理推广到n维射影空间的m次超曲面中,证明了n-单纯形上的Pascal点位于一个m次Pascal超曲面的充要条件是其每个2维面上的Pascal点分别位于m次平面Pascal空间的一条代数曲线上.进一步,给出了一定条件下m次Pascal超曲面与m-1次Pascal超曲面之间的内在关系.     

一种新的二维区域上嵌入式数值积分公式构造方法

The purpose of this paper is to study a new strategy to construct embedded cubature formulae over two-dimensional regions.A new kind of embedded cubature formulae with some nodes along the selected algebraic curve is constructed.Some examples on the unit disk are presented to illustrate the validity of this strategy.     

一类新的细分曲线方法

Subdivision defines a smooth curve or surface as the limit of a sequence of successive refinements based on initial control polygon or grid.Usually the curve refinements is the basis of the corresponding surface rules. In this paper we analyze previous subdivision scheme according to theories about convergence of N.Dyn and M.F Hassan. In terms of binary and ternary subdivision schemes general construction about curve‘s refinements are studied.Two approximating curve subdivision schemes with neighboring four control points are derived,the generating limit curves can both reach the smoothness of C^1 over the initial polygon using the two schemes and the tolerances of them are given according to the method of [7].     

紧扣知识关键点 激发学生学习兴趣——《数值逼近》课程教学的一些体会

多数本科生常常为如何提高学习兴趣、怎样在学习中获得"乐趣"而苦恼.而在教学过程中又该怎样激发学生们的学习兴趣也是每一位教师所面临的不可回避的问题.本文将结合多次讲授本科生《数值逼近》课程的亲身体会,就如何紧扣知识的关键点来激发学生的学习兴趣方面做些探讨.希望本文在使学生能够产生"局部"思维到"整体"思维的变化,提高对所学知识的好奇乃至兴趣方面有所帮助.     

Morgan-Scott型剖分上的样条空间的奇异性

Multivariate spline function is an important research object and tool in Computational Geometry. The singularity of multivariate spline spaces is a difficult problem that is ineritable in the research of the structure of multivariate spline spaces. The aim of this paper is to reveal the geometric significance of the singularity of bivariate spline space over Morgan-Scott type triangulation by using some new concepts proposed by the first author such as characteristic ratio, characteristic mapping of lines （or ponits）, and characteristic number of algebraic curve. With these concepts and the relevant results, a polished necessary and sufficient conditions for the singularity of spline space S u＋1^u （△MS^u） are geometrically given for any smoothness u by recursion. Moreover, the famous Pascal＇s theorem is generalized to algebraic plane curves of degree n≥3.     

一类多元全次数 Hermite 插值问题研究

In this paper we study a class of multivariate Hermite interpolation problem on 2~d nodes with dimension d ≥ 2 which can be seen as a generalization of two classical Hermite interpolation problems of d = 2. Two combinatorial identities are firstly given and then the regularity of the proposed interpolation problem is proved.     

给定零点的最近复系数多项式计算问题

Nearest polynomial with given properties has many applications in control theory and applied mathematics. Given a complex univariate polynomial f(z) and a zero α, in this paper we explore the problem of computing a complex polynomial f(z) such that f(α) = 0 and the distance ∥f-f ∥ is minimal. Considering most of the existing works focus on either certain polynomial basis or certain vector norm, we propose a common computation framework based on both general polynomial basis and general vector norm, and summarize the computing process into a four-step algorithm. Further, to find the explicit expression of f(z), we focus on two specific norms which generalize the familiar lp-norm and mixed norm studied in the existing works, and then compute f(z) explicitly based on the proposed algorithm. We finally give a numerical example to show the effectiveness of our method.     

基于逼近型细分的诱导细分格式

利用逼近型细分构造插值型细分是细分领域中的一个重要问题,目前可以给出插值型细分生成函数的研究还非常少.本文给出一个生成函数的统一公式,该公式由逼近型细分的生成函数与一个子生成函数构成.该公式对应一个插值型细分或者逼近型细分,这个取决于子生成函数的选取.该公式在理论和实际中都很重要.首先,这个公式适用于任意伸缩矩阵的多元基本型细分;其次,不论是一元细分还是多元细分,推导这个统一公式都不需要求解线性方程组;再次,这个公式具有显著的几何意义,应用方便;最后,从理论上分析诱导细分的零条件和多项式再生性,本文发现这些性质不仅与逼近型细分的零条件有关,而且与逼近型细分的多项式再生性有关,从而对细分格式的构造有指导意义.本文给出3个例子来说明这个统一公式.     

球面上的几何连续插值

In this paper, a new method for geometrically continuous interpolation in spheres is proposed. The method is entirely based on the spherical B′ezier curves defined by the generalized de Casteljau algorithm. Firstly we compute the tangent directions and curvature vectors at the endpoints of a spherical B′ezier curve. Then, based on the above results, we design a piecewise spherical B′ezier curve with G 1 and G 2 continuity. In order to get the optimal piecewise curve according to two different criteria, we also give a constructive method to determine the shape parameters of the curve. According to the method, any given spherical points can be directly interpolated in the sphere. Experimental results also demonstrate that the method performs well both in uniform speed and magnitude of covariant acceleration.