对调和级数性态的研究

将调和级数分别去掉那些分母是奇数的项、分母是偶数的项、分母是质数的项、分母是合数的项,所得无穷级数仍发散.利用欧拉常数的概念可证明调和级数发散.     

最小发散级数和最大收敛级数不存在理论及其论证

无穷级数是高等数学中的一部分重要内容.在判断无穷级数收敛或发散时,比较原理(比较审敛法或比较判别法)是一个有效的判别法,其基本原理是:     

茶楼对联话说"零"

人称"π无穷",奥数尖子生,两江三镇小有名;听说,九头鸟茶楼开张,一副对联出得巧,引起很多人争论.他一大早就跑来看究竟.常言道:莫道君行早,更有早行人.他人还未到,茶楼下已争不停."π无穷"抬头看对联,一边看来一边听,原来如此,争来争去为个"零".……     

一般项趋于零且部分和有界的发散级数

构造一个发散的任意项无穷级数,该级数的一般项趋于零且部分和数列有界.     

还有比调和级数发散速度更慢的正项级数吗

本文从调和级数前n项和的欧拉估计出发,定义正项发散级数发散速度序列,给出判别正项级数发散速度快慢法则.并依据此法构造出发散速度无限降低的正项级数序列,其比调和级数发散速度更慢.     

关于积分上限函数的周期性研究

探讨积分上限函数的周期性.得到积分上限函数是周期函数的两个充分必要条件.并得到当被积甬数是周期函数时.无穷限的反常积分发散性的一个结论.     

广义数的K层极限与K层积分

本文主要结果如下: 1.合理地用无穷小量的方法定义了极限。 2.证明了无穷小说法与ε-δ说法的极限定义是完全相当的。 3.能确定无穷发散积分的值。 例1 例2 由下式可以算出经典电子半径 η=2.818×10~(13)cm(c,光速,…)     

调和级数的一个有趣性质

对于调和级数sum from n=1 to ∞(1/n),它是一个发散的无穷级数,但笔者对其稍作变形,发现它有一个很有趣的性质.即性质:调和级数sum from n=1 to ∞(1/n),如果在调和级数中删去分母中含有数字1,2,3,…9 中任一个的所有项,则所得无穷级数将都收敛,且其和小于30.     

"无穷小的比较"的定义及其改进

"无穷小的比较"的现有定义有多种表述形式,但其中不少表述尚不够准确,有失严谨,甚至会导致错误命题的出现.引入"基"概念可使无穷小及无穷小比较的定义更为严谨、简洁、一般化.将无穷小量按含O值点的不同情况分为2类,有利于找出"无穷小的比较"现有定义中存在的问题.通过调整大前提,解决了定义项与被定义项外延不一致的问题;通过转...     

蠕动流中圆球阻力系数的入口效应

本文研究了圆球在半无穷长圆管入口处的蠕动流。得到了速度分布,压力分布和流函数的无穷级数形式的分析解.采用配置法将无穷级数截断并确定出级数中各项系数.求出了均匀入口流绕静止圆球以及圆球以瞬时速度在管内静止流体中运动这两种情形下圆球的阻力系数以及圆球表面上的应力分布.结果表明,当圆球在入口处运动时会遭受到较无穷圆管内为大的阻力.本文还对配置法的收敛性进行了数值实验.试验证明,该法具有好的收敛性.     

Minimum divergence estimators,maximum likelihood and exponential families

The dual representation formula of the divergence between two distributions in a parametric model is presented. Resulting estimators do not make use of any grouping or smoothing. For smooth divergences they all coincide with the MLE on any regular exponential family.     

Linear Systems Arising for Second-Order Mimetic Divergence and Gradient Discretizations

Recent investigations by Castillo and Grone have led to a new method for constructing mimetic discretizations of divergence and gradient operators. Their technique, which employs a matrix formulation to incorporate mimetic constraints, is capable of producing approximations whose order at a grid boundary is equal to that in the grids interior. In this paper, we construct a second-order mimetic discretization using Castillo and Grones approach and compare it to other second-order discretizations by applying them to an elliptic boundary value problem in one dimension. A detailed perturbation analysis is provided to offer some insight into the two discretizations yielding the best numerical results in the study.Mathematics Subject Classifications (2000) 65D25, 65M06, 65G99.This paper is an expanded version of the article [2] presented at the International Conference on Parallel and Distributed Processing Techniques and Applications held in Las Vegas, Nevada in June of 2003.     

Projective dynamics and classical gravitation

We show that there exists a projective dynamics of a particle. It underlies intrinsically the classical particle dynamics as projective geometry underlies Euclidean geometry. In classical particle dynamics a particle moves in the Euclidean space subjected to a potential. In projective dynamics the position space has only the local structure of the real projective space. The particle is subjected to a field of projective forces. A projective force is not an element of the tangent bundle to the position space, but of some fibre bundle isomorphic to the tangent bundle. These statements are direct consequences of Appell’s remarks on the homography in mechanics, and are compatible with similar statements due to Tabachnikov concerning projective billiards. When we study Euclidean geometry we meet some particular properties that we recognize as projective properties. The same is true for the dynamics of a particle. We show that two properties in classical particle dynamics are projective properties. The fact that the Keplerian orbits close after one turn is a consequence of a more general projective statement. The fact that the fields of gravitational forces are divergence free is a projective property of these fields.      

Divergences without probability vectors and their applications

In general, divergences and measures of information are defined for probability vectors. However, in some cases, divergences are ‘informally’ used to measure the discrepancy between vectors, which are not necessarily probability vectors. In this paper we examine whether divergences with nonprobability vectors in their arguments share the properties of probabilistic or information theoretic divergences. The results indicate that divergences with nonprobability vectors share, under some conditions, some of the properties of probabilistic or information theoretic divergences and therefore can be considered and used as information measures. We then use these divergences in the problem of actuarial graduation of mortality rates. Copyright © 2009 John Wiley & Sons, Ltd.     

散度形式椭圆型方程弱解的Hlder连续性

运用了Moser迭代技巧,先择适当的检验函数,讨论了散度形式的椭圆型偏微分方程弱解的Hlder连续性.     

A novel distribution classifier

We present a novel classifier for a collection of nonnegative L¹ functions. Given two sets of data, one set coming from “similar” distributions labeled as normal, and the other unspecified labeled as abnormal. To understand the structure of normality, and further to classify new data with minimal errors, we propose to find the smallest CKL spheres (based on Csiszar divergences) including as many normal data as possible and excluding as many abnormal data as possible. We prove the existence and uniqueness of such a classifier.     

关于江泽坚等著《实变函数论》的一个小瑕疵

指出江泽坚等合编教材《实变函数论》[2-3]中的一处瑕疵.这个瑕疵起始于第二版,在第三版时又没更正,时间已有22年(1994-2016).鉴于此教材影响大,使用面广,我们特写此注记将此瑕疵指出,与作者和读者商榷.     

有关发散级数的一些探讨

通过对发散级数的探讨,得到了发散级数相加仍然发散的充分条件.同时,考虑了反常积分的相应问题.     

加权散度型算子的低阶特征值

本文研究欧氏区域上加权散度型算子的低阶特征值.利用Rayleigh-Ritz不等式,得到了这种算子的低阶特征估计.