关于等比数列一个结论的商榷

全日制普通高级中学教材 (试验修订本 (必修 ) ,人民教育出版社编 ,以下简称新教材 )《数学》第一册(上 )Ｐ133练习第 4题 :已知数列 {ａｎ}是等比数列 ,Ｓｎ 是其前ｎ项的和 ,求证Ｓ7,Ｓ14 -Ｓ7,Ｓ2 1-Ｓ14 成等比数列 .设ｋ∈Ｎ+,Ｓｋ,Ｓ2ｋ-Ｓｋ,Ｓ3ｋ-Ｓ2ｋ成等比数列吗 ?由等比数列前ｎ项和的定义及通项公式 ,很容易证明Ｓ7,Ｓ14 -Ｓ7,Ｓ2 1-Ｓ14 成等比数列 .教学参考书上指出 :可类似地证明Ｓｋ,Ｓ2ｋ-Ｓｋ,Ｓ3ｋ-Ｓ2ｋ成等比数列 .我们认为 ,对等比数列而言 ,Ｓ7,Ｓ14 -Ｓ7,Ｓ2 1-Ｓ14 成等比数列 ,但Ｓｋ,Ｓ2ｋ-Ｓｋ,Ｓ3ｋ-Ｓ2ｋ不…     

“Katona-Kleitman定理的推广定理”的简短证明

本文给出“Ｋａｔｏｎａ－Ｋｌｅｉｔｍａｎ定理的推广”的简短证明．设Ｓ是ｎ元集合,Ｓ１,Ｓ２,…,Ｓｋ是 Ｓ的ｋ分划,Ｆ是Ｓ的子集系, 使得没有Ａ,Ｂ∈Ｆ,满足存在某个Ｓｉ有Ａ∩Ｓｉ＝Ｂ∩Ｓｉ,而对所有Ｓｉ＜（１＜ｉ≠ｉ＜ｋ）有Ａ∩∨ＳｉＢ∩Ｓｉ,则｜Ｆ｜     

The Structure of NBe—rpp Semigroups

§ 1.ＩｎｔｒｏｄｕｃｔｉｏｎａｎｄＭａｉｎＲｅｓｕｌｔｓ　ＡｓｅｍｉｇｒｏｕｐＳｉｓｃａｌｌｅｄａｎｒｐｐｓｅｍｉｇｒｏｕｐｉｆａｌｌｐｒｉｎｃｉｐａｌｒｉｇｈｔｉｄｅａｌｓａＳ1(ａ∈Ｓ)ｏｆＳ ,ｒｅｇａｒｄｅｄａｓａｎＳ1 ｓｙｓｔｅｍ ,ａｒｅｐｒｏｊｅｃｔｉｖｅ (ｓｅｅ,[1 ]ａｎｄ [2 ] ) .ＡｓｅｍｉｇｒｏｕｐＳｉｓａｎｒｐｐｓｅｍｉｇｒｏｕｐｉｆａｎｄｏｎｌｙｉｆｆｏｒａｌｌａ∈Ｓ ,ｔｈｅｓｅｔＭａ ={ｅ∈Ｅ Ｓ1ａ Ｓｅａｎｄ ( ｘ ,ｙ∈Ｓ1)ａｘ=ａｙ ｅｘ=ｅｙ}ｉｓｎｏｎｅｍｐｔｙ ,ｗｈｅｒｅＥ …     

关于Clifford半群S和Brandt半群S的S的构造(英文)

设Ｓ是半群,Ｓ是Ｓ上所有一一偏的右平移构成的逆半群．在本文中证明了,对Ｃｌｉｆｏｒｄ半群Ｓ＝［Ｙ;Ｇα,φα,β］,Ｓｉｍｌｉｍ｛Ｇα｝α∈Ｙ,而对Ｂｒａｎｄｔ半群Ｓ＝Ｂ（Ｇ,Ｉ）,ＳＧｗｒＪ（Ｉ）．     

A Note on C-wrpp Semigroups

ＬｅｔＲｄｅｎｏｔｅＧｒｅｅｎ ｓＲ ｒｅｌａｔｉｏｎｏｎａｓｅｍｉｇｒｏｕｐＳ .ＷｅｄｅｆｉｎｅａｒｉｇｈｔｃｏｎｇｒｕｅｎｃｅＬ ｏｎＳｉｎｔｈｅｒｕｌｅ:ｆｏｒａ ,ｂ∈Ｓ ,(ａ ,ｂ) ∈Ｌ ｉｆｆｆｏｒａｌｌｘ ,ｙ∈Ｓ1,　　 (ａｘ ,ａｙ) ∈Ｒ (ｂｘ,ｂｙ) ∈Ｒ .ＡｓｅｍｉｇｒｏｕｐＳｉｓｓａｉｄｔｏｂｅａＣ ｗｒｐｐｓｅｍｉｇｒｏｕｐｉｆａｌｌｉｄｅｍｐｏｔｅｎｔｓｏｆＳａｒｅｃｅｎｔｒａｌｉｎＳａｎｄｅａｃｈＬ ｃｌａｓｓｏｆＳｃｏｎｔａｉｎｓａｎｉｄｅｍｐｏｔｅｎｔ(ｓｅｅ [1 ] ) .　Ｔｈｅｐ…     

PPS整群抽样下的比估计量

本文研究有辅助指标的ＰＰＳ整群抽样,构造了总体均值和总值的ＰＰＳ比估计量,证明ＰＰＳ比估计量是可用的,给出ＰＰＳ比估计量优于ＰＰＳ估计量的条件并讨论其优良性．     

公式2(S_0)1/2=S1/2 (S′)1/2的推广与应用

在高一《立体几何》中 ,关于台体 (棱台、圆台 )的中截面有这样的一个性质 :2Ｓ0 =Ｓ Ｓ′(《立体几何》Ｐ64 例 2及Ｐ80 习题十第 1 1题 ) .换句话说 ,台体 (棱台、圆台 )的上底面面积Ｓ′、中截面面积Ｓ0 、下底面面积Ｓ的算术平方根Ｓ′、Ｓ0 、Ｓ组成了一个等差数列 ,公差ｄ =12 Ｓ -Ｓ′ .是不是只有中截面与上、下底面的面积具有这种性质 ?其它截面与上、下底面的面积是否具有类似的性质 ?我们不仿看一下 .设台体 (棱台、圆台 )的上、下底面面积分别是Ｓ′、Ｓ ,台体 (棱台、圆台 )的高为ｎｈ ,设Ｓ1 、Ｓ2 …Ｓｎ- 1 分别是过台体 (…     

公式2(S_0)~1/=(S_上)~1/2 (S_下)~1/2的思考

设棱台的两底面积分别为Ｓ上,Ｓ下,棱台中截面面积为Ｓ０,则有２Ｓ０＝Ｓ上＋Ｓ下．此公式的结构使我们易于联想到解析几何的中点坐标公式．下面以三棱台为例探索问题的一般形式．为方便起见,这里约定棱台上、下底面,平行于底面的截面面积分别用Ｓ上,Ｓ下,Ｓ表示．...     

岭回归分析的SAS程序设计

田俊．岭回归分析的ＳＡＳ程序设计．岭回归分析方法是传统的多元回归分析方法的一个补充,在实际工作中经常使用。但是在标准统计软件ＳＡＳ中没有专门的岭回归分析过程,本文介绍如何通过设置伪样品后使用ＳＡＳ进行岭回归分析     

新教材中一道数列题的错解诊断

20 0 0年人教版《全日制普通高级中学教科书(实验修订本·必修 )数学第一册 (上 )》第 133页§ 3.5练习第 4题如下 :已知数列 {ａｎ}是等比数列 ,Ｓｎ 是其前ｎ项的和 ,求证 :Ｓ7,Ｓ14 -Ｓ7,Ｓ2 1-Ｓ14 成等比数列 .设ｋ∈Ｎ ,Ｓｋ,Ｓ2ｋ-Ｓｋ,Ｓ3ｋ-Ｓ2ｋ成等比数列吗 ?与教材配套的《教师教学用书》第 87— 88页对此题给出如下参考解答 :由Ｓ7=ａ1(1- ｑ7)1- ｑ ,Ｓ14 =ａ1(1- ｑ14 )1- ｑ ,Ｓ2 1=ａ1(1- ｑ2 1)1- ｑ ,可得Ｓ7(Ｓ2 1-Ｓ14 ) =(Ｓ14 -Ｓ7) 2 ;此结论也可如下证明Ｓ14 -Ｓ7=(ａ1 ａ2 … ａ14 ) - (ａ1 ａ2 … ａ7) =ａ8 …     

Effective medium model for flow through beds of porous cylindrical fibres

We have used effective medium model for beds of circular cylindrical porous fibres in order to estimate the overall bed permeability (OBP). It is assumed that a representative circular porous cylindrical fibre is inside a fluid envelope beyond which effective medium is used. Both inside the cylindrical fibre and in the effective medium, Brinkman equation is used, however of different permeabilities and in the fluid envelope Stokes equation is used. The OBP corresponding to the porous fibres is estimated when the flow direction is perpendicular to the axis of the cylindrical fibres as well as parallel to the fibres. This in turn is used to estimate the OBP corresponding to a collection of porous cylindrical fibres that are randomly oriented. We have compared the results with some existing literature.     

Pricing used products for remanufacturing

Remanufacturing is one of recovery options for used products. As remanufacturing requires a continuous supply of used products, the economic incentive is required to attract customers to return their used products (called cores) and the problem of pricing a core becomes an important issue. Such a pricing problem is analogous to pricing an option, which can be used to sell the remanufactured cores (called core products). As sales price of core products follows a geometric Brownian motion, we propose a model here to evaluate the acquisition price of cores. This model links core acquisition price with the sale price of core product but assumes other costs such as logistics and remanufacturing to be deterministic. We have presented a numerical example to show its applicability. Since the model proposed here is generic, it is believed that the proposed model can be used in setting the core prices in many situations.     

A new forecasting method for time continuous model of dynamic system

Usually a linear differential equation is used to represent continuous dynamic systems, but a linear difference equation is used to represent discrete dynamic systems. AGO is one of the most important characteristics of grey theory, and its main purpose is to reduce the randomness of data. A linear differential equation, instead of a linear difference equation, is used to replace the grey differential equation to analyze discrete systems in this paper. Approximating a k-order derivative by operating after spline curve fitting of 1-AGO data, a model is directly established by means of the least square method. ARIMA models are used to analyze the leading indicator in advance, and the Fourier series with suitably chosen values of parameters is used in the fitting of leading indicator. This model is called the GDM(2, 2, 1) model.     

有保护区的海洋渔业资源离散动力学模型分析

假设海洋渔业资源分属于保护区和非保护区两个区域,本文建立一个渔业资源储量-捕捞力度模型,用聚合方法得到一个简化的离散动力系统,从而分析正不动点的存在性、稳定性以及关于保护区面积比例的局部分叉,运用中心流形定理分析平衡点的局部稳定性,并用数值模拟验证不动点的局部分叉.最后,用全局分析方法分析保护区面积比例变化对可行吸引域的结构和大小的影响,从而揭示保护区对渔业资源可持续利用的影响.     

多孔介质二相驱动问题一种修正特征有限元方法的迭代解法及其收敛性分析

0 引言 多孔介质二相驱动问题的数学模型是由压力方程与浓度方程组成的偏微分方程组的初边值问题.关于该问题的数值解问题,已有大量的文献.为了得到最优的L~2-模误差估计,好多方法用混合元方法解压力方程.我们知道,混合元法得到的方程组系数矩阵是非正定的,从而解混合元比解标准元要困难得多,虽然许多人研究了混合元方法的求解问题,但到目前为止,还没有看到令人满意的好的算法.为了避开对混合元的求解,著名学者T.F.Russell考虑了用标准有限元方法解压力方程,用特征有限元方法解浓度方程的求解方法及其迭代解法,对只有分子扩散的二相驱动问题得到了最优的L~2模误差估计,对有机械弥散的一般二相驱动问题得不到最优的L~2模误差估计,同时在收敛性证明中要求压力有限元空间的指数至少是二.     

A new forecasting method of discrete dynamic system

Usually, a linear differential equation is used to represent continuous dynamic systems, but a linear difference equation is used to represent discrete dynamic systems. AGO is one of the most important characteristics of grey theory, and its main purpose is to reduce the random of data. A linear differential equation, instead of a linear difference equation, is used to replace the grey differential equation to analyze discrete systems in this paper. The k-order derivatives of 1-AGO data are calculated after cubic spline interpolation of them, and the model parameters are estimated by means of the deterministic convergence scheme. ARIMA models are used to analyze the leading indicator in advance, and Fourier series with suitably chosen values of parameters is used for fitting the leading indicator. The model presented in this paper is called Grey Dynamic Model GDM(1,1,1).     

New monotone hybrid algorithm for hemi-relatively nonexpansive mappings and maximal monotone operators

The purpose of this article is to prove the strong convergence theorems for hemi-relatively nonexpansive mappings in Banach spaces. In order to get the strong convergence theorems for hemi-relatively nonexpansive mappings, a new monotone hybrid iteration algorithm is presented and is used to approximate the fixed point of hemi-relatively nonexpansive mappings. Noting that, the general hybrid iteration algorithm can be used for relatively nonexpansive mappings but it can not be used for hemi-relatively nonexpansive mappings. However, this new monotone hybrid algorithm can be used for hemi-relatively nonexpansive mappings. In addition, a new method of proof has been used in this article. That is, by using this new monotone hybrid algorithm, we firstly claim that, the iterative sequence is a Cauchy sequence. The results of this paper modify and improve the results of Matsushita and Takahashi, and some others.     

An atomic interaction-based rod formulation for modelling Gecko adhesion

We present a nonlinear rod model which describes the adhesion mechanism used by the Gecko to cling to inclined and overhanging surfaces. The rod formulation is used to model the fine, hair–like setae, which form the microstructure of the Gecko toes. A simple geometric representation, based on hyperbolas, is used to capture the branching of the seta. The adhesion between seta and surface is modelled by an atomic interaction potential. The seta model is cast into a nonlinear finite element framework, which is used to simulate and study the pull–off behavior of a single seta. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

A strategy for analysing mixed and pooled exponentials

It is shown that a linear plot of the mean residual life on the failure rate characterizes the mixture of two exponentials. This plot is used to estimate the two components in the mixing distribution with the two largest mixing proportions. The EM algorithm is then used with these as initial values to obtain the MLE. Gradient plots are used to see if a higher-order fit is needed. A heuristic is given on how to use the gradient plots to identify components in the higher-order fit when this is the case. Graphs of an assignment function are then used to determine if the data are from a mixed model or simply the effect of pooling.     

A generalised ratio identity

An identity is derived relating the distribution of a continuous time, skip-free process with two impenetrable barriers to the distribution of a process with one barrier. It is indicated how the methods used here can also be used to give results for related processes with different types of barriers. The identity is then used to derive explicit results giving the distribution of the process with two impenetrable barriers.