共查询到20条相似文献,搜索用时 856 毫秒
1.
特殊形式的多元有理样条插值 总被引:2,自引:0,他引:2
有理样条插值问题最早是由R.Schaback提出的,由于R.Schaback考虑此问题时涉及到了非线性方程组的求解,因而实现起来比较复杂.后来,王仁宏等研究了几类特殊形式的插值有理样条函数,避开了求解非线性方程的困难.能否在多元情形下建立类似的结果?本文对此作出了肯定的回答,并就二元情形的三角剖分和四边形剖分建立了几类特殊形式的插值多元有理样条,构造性地证明了解的存在性和唯一性. 相似文献
2.
冯康 《数学的实践与认识》1975,(1)
§2. 剖分插值 本节讨论平面区域的几何剖分和相应的分片插值方法.对区域进行剖分时,基本单元可以取为三角形、矩形、四边形等等.插值函数可以取为一次(线性)或高次多项式等等.其中以三角剖分和相应的三顶点线性插值最简单,最常用,故主要讨论这一情况.为了尽快进入有限元离散化,可以只读这里的§§2.1-3而转至§3. 相似文献
3.
一类分层三角剖分下三次样条空间的维数 总被引:1,自引:0,他引:1
本文定义了平面单连通多边形域的一类较任意的三角剖分-分层三角剖分,并通过分析二元样条的积分协调条件,确定了分层三角剖分卜三次C1作条函数空间的维数. 相似文献
4.
1引言随着计算机科学技术的发展,多元样条在力学和计算机辅助几何设计(CAGD)中的应用越来越引起人们极大兴趣.然而,由于一般剖分下样条空间的研究有相当的难度,迄今为止只对于一些特殊剖分的样条空间取得了一定的进展,如:矩形剖分,均匀的1-型,2-型三角剖分等.王仁宏和崔锦泰讨论了均匀2-型三角剖下的拟插值算子以及其逼近性质,鉴于在工程和实际应用中均匀剖分具有一定局限性,作者在文献([1],[3])的基础上,对于非均匀2-型三角剖分,给出了一类拟插值算子,并研究了它的逼近性质.同时,利用其构造了一类… 相似文献
5.
我们构造了关于 R~n 的一种新的三角剖分——D_1三角剖分,且证明了它比熟知的三角剖分的单纯形个数都少.基于 D_1三角剖分,我们建立了一种新的变维数单纯算法.几个数值例子表明新的 D_1三角剖分及算法的确是更有效的. 相似文献
6.
7.
8.
柱面上的三角剖分是一类与环面上的地图紧密相关的地图.本文提供了一个计算柱面上有根近三角剖分的具有三个变量的精确公式. 相似文献
9.
10.
11.
C P ANIL KUMAR 《Proceedings Mathematical Sciences》2017,127(1):69-90
Many questions about triangles and quadrilaterals with rational sides, diagonals and areas can be reduced to solving certain diophantine equations. We look at a number of such questions including the question of approximating arbitrary triangles and quadrilaterals by those with rational sides, diagonals and areas. We transform these problems into questions on the existence of infinitely many rational solutions on a two parameter family of quartic curves. This is further transformed to a two parameter family of elliptic curves to deduce our main result concerning density of points on a line which are at a rational distance from three collinear points (Theorem 4). We deduce from this a new proof of density of rational quadrilaterals in the space of all quadrilaterals (Theorem 39). The other main result (Theorem 3) of this article is on the density of rational triangles which is related to analyzing rational points on the unit circle. Interestingly, this enables us to deduce that parallelograms with rational sides and area are dense in the class of all parallelograms. We also give a criterion for density of certain sets in topological spaces using local product structure and prove the density Theorem 6 in the appendix section. An application of this proves the density of rational points as stated in Theorem 31. 相似文献
12.
苏战军 《数学的实践与认识》2004,34(1):145-149
1970年 Monsky证明了正方形不能划分为奇数个面积相等的三角形 .Stein等人对梯形的等面积三角形划分作了深入的研究 ,得到了大量结果 .本文就未解决的问题作了进一步的讨论 ,即讨论一类特殊梯形的等面积三角形划分问题 . 相似文献
13.
In 1970 Monsky proved that a square cannot be cut into an odd number of triangles of equal areas. In 1990 it was proved that the statement is true for any centrally symmetric polygon. In the present paper we consider dissections of general polygons into triangles of equal areas. 相似文献
14.
Daniela Ferrarello Mario Pennisi 《International Journal of Mathematical Education in Science & Technology》2018,49(4):628-641
In this paper, we show some properties of centroids of geometric figures, such as triangles, quadrilaterals and tetrahedra. In particular, we will prove the properties by means of geometric transformations and by introducing extensions of triangles and quadrilaterals, i.e. by adding one, two or three new vertices to the figure. The study of these properties can be used, with profit, in a classroom activity supported by a dynamic geometry system. 相似文献
15.
The P1-nonconforming finite element method on simply connected Lipschitz domains partitioned into quadrilaterals was introduced by Park and Sheen in 2003. In order to apply mesh-adaptive refinement strategies, the concept is generalized to arbitrary triangulations into quadrilaterals and triangles of multiple connected Lipschitz domains. An explicit a priori analysis is given for second-order elliptic PDEs with inhomogeneous Dirichlet boundary conditions. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
16.
Maria Flavia Mammana 《International Journal of Mathematical Education in Science & Technology》2016,47(7):1103-1119
In this paper, we use geometric transformations to find some interesting properties related with geometric loci. In particular, given a triangle or a cyclic quadrilateral, the locus generated by the centroid or by the orthocentre (for triangles) or by the anticentre (for cyclic quadrilaterals) when one vertex moves on the circumcircle of the figure are considered. These loci are studied in paragraphs 3 and 4. By means of the homothetic transformations some properties of triangles and quadrilaterals are found. The study of these properties can be used, with profit, in a classroom activity supported by Dynamic Geometry System. 相似文献
17.
In this paper we find the set of integers for which there exists a linear space having all lines of degree four with the property that the set of lines can be partitioned into the classical configurations: complete quadrilaterals, triangles and 4-gons. 相似文献
18.
一、引言 二元函数在标准三角形上的混合函数插值格式在许多文献,例如,Birkhofft,Barnhill,Gordon及Gregory等的文章中都有讨论。在三角形周边上对高阶偏导数进行插值,而且计算比较简单的是J.A.Gregory的文章中所给出的一种混合函数插值格式。这种格式是由简单函数的线性组合所构成的,而且格式是对称的,因此计算比较简便。但是J.A.Gregory只是对直边三角形给出了格式。本文企图推广Gregory的格式,给出曲边三角形上对高阶偏导数进行插值的插值格式。我们还进一步给出了曲边四边形上 相似文献
19.
Dissections of regular polygons into triangles of equal areas 总被引:2,自引:0,他引:2
E. A. Kasimatis 《Discrete and Computational Geometry》1989,4(1):375-381
This paper answers the question, “If a regular polygon withn sides is dissected intom triangles of equal areas, mustm be a multiple ofn?” Forn=3 the answer is “no,” since a triangle can be cut into any positive integral number of triangles of equal areas. Forn=4 the answer is again “no,” since a square can be cut into two triangles of equal areas. However, Monsky showed that a square cannot be dissected into an odd number of triangles of equal areas. We show that ifn is at least 5, then the answer is “yes.” Our approach incorporates the techniques of Thomas, Monsky, and Mead, in particular, the use of Sperner's lemma and non-Archimedean valuations, but also makes use of affine transformations to distort a given regular polygon into one to which those techniques apply. 相似文献
20.
抛物类二次曲线外切多边形中有向面积的定值定理及其应用 总被引:4,自引:0,他引:4
利用有向面积定值法,对抛物线外切多边形中的对角线三角形和切点三角形之间的关系进行研究,得到抛物类二次曲线外切n边形(n≥4)中有向面积的一个定值定理,并据此推出抛物线外切多边形中三线共点的点多达n(n-3)个,以及射影几何中著名的Brianchon定理等结论. 相似文献