首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 250 毫秒
1.
本文研究了带根4-正则单行平面地图的计数问题,并给出了以其非根点数和两个奇点次为三个参数的一些计数公式.  相似文献   

2.
一类带有三次项的平面五次微分系统在Poincare变换下可以讨论系统的无穷远奇点的性质,进而得到奇点附近轨线的拓扑结构,并利用判断函数给出极限环存在与否的条件,补充完善了五次系统的定性分析.  相似文献   

3.
本文提供了广义冬梅地图以根点次,非根点数和内面数为参数的计数函数所满足的一些函数方程,其中有两个为三次方程,并进一步导出了它们的计数显式。  相似文献   

4.
该文建立超越亚纯函数与整函数的复合函数的有理函数值点密指量,借助第二个因子的增长性的一个定量估计,其中用到在本性奇点邻域上的Nevanlinna理论.  相似文献   

5.
本文对于矩形区域上某一内点为奇点的奇异积分的近似计算给出了优化中心数值算法,它在迭代计算过程中避免了函数值的重复计算.采用外推法减少迭代次数.  相似文献   

6.
留数又称残数,它是复变函数论中的一个重要概念,但Matlab中的Residue函数仅能处理多项式分式函数.本文首先根据孤立奇点的特点,提出了用Matlab确定极点阶次的方法,然后再根据高阶极点的留数公式,基于符号运算计算该极点处的留数.在此过程中,还解决了Matlab无法直接求解复数点处极限的问题.该方法的优点是不需要事前判断极点阶次,可以计算任意类型函数的留数,使得留数的计算更加简单.  相似文献   

7.
本文构造了一个有趣的复变函数.此函数不但有一个非孤立的奇点,而且该函数在这个奇点处是可导的.  相似文献   

8.
本文对于矩形区域上某一内点为奇点的奇异积分的近似计算给出了优化中心数值算法,它在迭代计算过程中避免了函数值的重复计算.采用外推法减少迭代次数.  相似文献   

9.
孙建华 《中国科学A辑》1994,37(11):1145-1151
考虑具有两个非双曲奇点的n维异宿系统。对这类Rn中的高余维分支问题,求得Melnikov型向量分支函数,以保证在两个非双曲奇点所分裂出的新奇点间存在异宿轨线。  相似文献   

10.
补偿凸上变换和下变换是对给定函数作"紧贴"逼近的单参数单向变换.本文将它们应用到R~n中局部具有一般模的半凸/半凹函数和DC-函数(即两个凸函数的差函数)的奇点提取.(局部)半凹函数最常见的几何例子有Euclid距离函数和平方Euclid距离函数.对于局部具有一般模的半凸函数f,本文证明在局部意义下,x是f的奇点(即不可微点)当且仅当它是f的1-阶"谷点",因而用本文的方法可以从具有一般模的局部半凸函数中提取所有的这些精细的几何奇点.更确切地讲,如果f是局部具有一般模的半凸函数,则"局部的"1-阶"山谷"变换在每个点x的极限存在,而且有显式表示lim_(λ→+∞)λV_λ(f)(x)=r_x~2/4,其中Vλ(f)(x)是f在x点的"山谷"变换,rx是f在x点次微分?-f(x)的最小包含球面的半径.所以,极限函数V∞(f)(x):=lim_(λ→+∞)λV_λ(f)(x)=r_x~2/4提供了一个半凸函数奇点1-阶"谷点"的"景观函数".同时,它也提供了补偿上凸变换Cuλ(f)(x)当λ→+∞时的一阶渐近展开式.对于具有局部线性模的局部半凸函数,本文进一步证明,补偿凸上变换的梯度当λ→+∞时的极限lim_(λ→+∞)▽C_λ~u(f)(x)存在,并且这个极限等于次微分?-f(x)的最小包含球面的中心.对于DC-函数f=g-h,本文证明它的1-阶"边缘"变换,当λ→+∞时满足lim inf_(λ→+∞)λE_λ(f)(x)(r_(g,x)-r_(h,x))~2/4,其中r_(g,x)和r_(h,x)分别是次微分?-g(x)和?-h(x)的最小包含球面的半径.  相似文献   

11.
In a rooted planar map, the rooted vertex is said to be non-separable if the vertex onthe boundary of the outer face as an induced graph is not a cut-vertex. In this paper, the author derives a functional equation satisfied by the enumeratingfuuction of rooted vertex non-separable planar maps dependent on the edge number and thenumber of the edges on the outer face boundary, finds a parametric expression of itssolution, and obtains an explicit formula for the function. Particularly, the number of rooted vertex non-separable maps only replying on theedge number and that of rooted vertex non-separable tree-like maps defined in [4] accordingto the two indices, the edge number and the number of the edges on the outer face boundary,or only one index, the edge number, are also determined.  相似文献   

12.
ENUMERATING ROOTED EULERIAN PLANAR MAPS   总被引:2,自引:0,他引:2  
1 IntroductionSince Thtte's papers oll enunlerating planar InaPs in [7,8] published iu the beginlling Ofsixties, the enumerative theory has been developed greatly up to now. The enumeration ofgenera1 Eulerian planar maps is dependent on two paranleters as the valency of rooted vertexalld the uunther of edges Of the nmps. Y.P.Liu found tl1e functional equation firstly for thenlaPs aud then obtained the number of general rooted Elllerian planar maPs with the nuntherof edges given in 1989[1].…  相似文献   

13.
In 1966, Barnette introduced a set of graphs, called circuit graphs, which are obtained from 3-connected planar graphs by deleting a vertex. Circuit graphs and 3-connected planar graphs share many interesting properties which are not satisfied by general 2-connected planar graphs. Circuit graphs have nice closure properties which make them easier to deal with than 3-connected planar graphs for studying some graph-theoretic properties. In this paper, we study some enumerative properties of circuit graphs. For enumeration purpose, we define rooted circuit maps and compare the number of rooted circuit maps with those of rooted 2-connected planar maps and rooted 3-connected planar maps.  相似文献   

14.
A Halin map is a kind of planar maps oriented by a tree. In this paper the rooted halin maps with the vertex partition as parameters are enumerated such that a famous result on rooted trees due to Harary. Prins, and Tutte is deduced as. a special ease. Further, by using Lagrangian inversion to obtain a number of summation free formulae dixectly, the various kinds of rooted Halin maps with up to three parameters have been counted.  相似文献   

15.
这篇文章得到了以根节点的次、割边的个数及环的个数为参数的双树梵和的色和方程,且导出了这类地图带以上三个参数的精确解及一些退化的情形。  相似文献   

16.
The functional equation satisfied by the vertex partition function of rooted loopless Eulerian planar maps is provided. As applications, the enumerating equations for general and regular cases of this kind of maps are also discussed.This project is supported partially by the National Natural Science Foundation of China Grant 18971061.  相似文献   

17.
本文研究至多有两个无公共边圈的有根平面地图,提出了这种地图的节点剖分计数函数和以它的根次、边数和一次点数为三个参数的计数函数所满足方程。  相似文献   

18.
A unicellular map is a map which has only one face. We give a bijection between a dominant subset of rooted unicellular maps of given genus and a set of rooted plane trees with distinguished vertices. The bijection applies as well to the case of labelled unicellular maps, which are related to all rooted maps by Marcus and Schaeffer’s bijection. This gives an immediate derivation of the asymptotic number of unicellular maps of given genus, and a simple bijective proof of a formula of Lehman and Walsh on the number of triangulations with one vertex. From the labelled case, we deduce an expression of the asymptotic number of maps of genus g with n edges involving the ISE random measure, and an explicit characterization of the limiting profile and radius of random bipartite quadrangulations of genus g in terms of the ISE.  相似文献   

19.
In this paper, we study the chromatic sum functions of rooted general maps on the sphere and the projective plane. The chromatic sum function equations of such maps are obtained. From the chromatic sum equations of such maps, the enumerating function equations of rooted loopless maps, bipartite maps and Eulerian maps are also derived. Moreover, some explicit expressions of enumerating functions are also derived.  相似文献   

20.
李赵祥  刘彦佩 《数学学报》2004,47(3):487-494
本文研究了平面上一般带根地图的色和与双色和,得到了这类地图的色和与双色和函数方程。从这类地图的色和函数方程,导出了平面上一般无环地图、平面上二部地图和平面上欧拉地图的计数函数方程。还得到了一些计数函数的计数显式。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号