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 93 毫秒
1.
Let (X1,X2,…,Xn) and (Y1,Y2,…Yn) be real random vectors with the same marginal distributions,if (X1,X2,…,Xn)≤c(Y1,Y2,…Yn), it is showed in this paper that ∑i=1^n Xi≤cx∑i=1^n Yi and max1≤k≤n∑i=1^k Xi≤icx max1≤k≤n∑i=1^k Yi hold. Based on this fact,a more general comparison theorem is obtained.  相似文献   

2.
套链分解     
Let X1,X2,...,Xk be k disjoint subsets of S with the same cardinality m.Define H(m,k) = {X (C) S: X (C) Xi for 1 ≤I ≤k} and P(m,k) = {X (C) S : X ∩ Xi ≠φ for at least two Xi's}.Suppose S = Uki=1 Xi,and let Q(m,k,2) be the collection of all subsets K of S satisfying|K ∩ Xi|≥ 2 for some 1 ≤ I ≤ k.For any two disjoint subsets Y1 and Y2 of S,we define F1,j = {X (C) S : either |X ∩ Y1|≥ 1 or |X ∩ Y2|≥ j}.It is obvious that the four posers are graded posets ordered by inclusion.In this paper we will prove that the four posets are nested chain orders.  相似文献   

3.
设Fi(x)是Rp上总体Xi的分布函数,1≤i≤k.考虑假设问题H0:F1(x)=F2(x)=…=Fk(x),(A)z∈Rp,构造了一个检验统计量X2n,并证明当H0成立时,其渐近分布是自由度为k-1的X2分布.  相似文献   

4.
§ 1  IntroductionWe firstintroduce some concepts.Random variables X and Y are called negative dependent ( ND) if for any pair ofmonotonically non-decresing functions f and g,Cov{ f( X) ,g( Y) }≤ 0 .Clearly itis equivalenttoP( X≤ x,Y≤ y)≤ P( X≤ x) P( Y≤ y)for all x,y∈R.A random sequence{ Xi,i≥ 1 } is said to be negative quadrant dependent( NQD) if any pairof variables Xi,Xj( i≠j) are ND.A sequence of random variables{ Xi,i≥ 1 } is said to be linear negative quadrand depend…  相似文献   

5.
设{Xk,i;k≥1,i≥1)是一随机变量组列,令{pn;n≥1)是一正整数序列,满足c1≤n/pn≤c2,其中c1,c2是正实数.假设{Xk,i;k≥1,i≥1}满足一些相依条件,得到了Ln的渐近分布,这里Ln= ,以及表示(X1,i,…,Xn,i)'和(X1,j,…,Xn,j)'间的Pearson相关系数.  相似文献   

6.
设u_n 为R~n 中超平面 {u_n=(u_1,…,u_n):sum from i=1 to n u_i=1,u_i≥0,i=1,…,n}上的均匀分布。我们在文[3]中引入了一个和指数分布有关的多元对称分布族 _n={z:zru,r≥0与u独立}。设z_(1)≤…≤z_(n)为z=(z_1,…,z_n)∈_n的次序统计量。本文给出了z_(1),…,z_(n)的联合分布,一维和二维边缘分布以及极差和中程的分布。我们还求出了{z_(i)}的矩并讨论了次序统计量的应用。  相似文献   

7.
王志军 《数学通报》2005,44(9):54-54
容斥原理 设Xi(i=1,2,…,n)为有限集,则有:Card(U1≤i≤n Xi)=∑1≤i≤n Card(Xi)-∑1≤i≤j≤n Card(Xi∩Xj)+∑1≤i≤j≤n Card (Xi ∩ Xj ∩ Xk)+…+(-1)^n-1 Card (∩1≤i≤n Xj).  相似文献   

8.
设{Xi}∞i=1是标准化强相依非平稳高斯序列,记Sn=∑Xi,σn=√var(Sn),Mktn为X1,X2,…,Xtn的第k个最大值,Ntn为X1,X2,…,Xtn对水平μn(x)的超过数形成的点过程,tn是-列单调增加的正整数列,在一定条件下得到Ntn与Sn/σn,Mktn与Sn/σn的联合渐近分布.  相似文献   

9.
设X(n)=max(Xi),其中Xi(1≤i≤n)相互独立,均服从指数分布.利用指数分布的期望和二阶矩或通过讨论Xi的次序统计量,可求出X(n)的数学期望和方差.从两种不同解法可导出两个恒等式.  相似文献   

10.
1.IntroductionLetXI,X2,',X.beasequenceofnonnegativeindependentrandomvariableswithcommoncontinuousdistributionfunctionF.LetYI,Y2,',YebeanothersequenceofnonnegativeindependentrandomvariableswithcommoncontinuousdistributionfunctionG,alsoindependentof{Xi}.WecanonlyobserveZi=min(Xi,K),6i~I(x.SYi).OnewaytoestimatethedistributionfunctionForthesurvivalfunctionS~1--Ffromthesample(Zi,st)(i=l,2,')n)isthroughtheproductlimitestimatordueto[1].ItisdefinedbywhereZ(i)aretheorderstatisticsofZian…  相似文献   

11.
U-统计量的精致渐近性   总被引:1,自引:1,他引:0  
严继高  苏淳 《数学学报》2007,50(3):517-526
设{X_n.n≥1}是一非退化的i.i.d.随机变量序列,U_n是以二维Borel可测对称函数h(x,y)为核函数的U-统计量.记U_n=2/(n(n-1))Σ_≤i≤j≤nh(X_i,X_j).本文分别在核函数h(x,y)只有4/3阶矩或4/3+δ,0<δ≤1的情况下,对非常广泛的一类权函数(x)与边界函数b(x)得到了如下关于U-统计量U_n的精致渐近性:不仅使得已有的结果成为我们的特况,还大大降低了其中的矩条件.  相似文献   

12.
In this paper, we consider a central limit theorem for the sequence of stationary m-dependent random variables, the variance of which is possibly infinite. Theorem. Let {Xn, n=l, 2,...} be a sequence of stationary m-dependent random variables with means zero. The following conditions are satisfied. (i) \[{M^2}\int_{{\text{|}}{X_1}| > M} {dP} /\int_{{X_1}| < M} {X_1^2} dP \to 0{\kern 1pt} {\kern 1pt} {\kern 1pt} (M \to \infty )\] (ii) \[\int_{\{ {X_1}| < M,|{X_i}| < M} {X_1^{}} {X_i}dP/\int_{|{X_1}| < M} {X_1^2} dP \to 0{\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} (M \to \infty )\] then there are constants Bsubsub>0, such that \[\frac{1}{{{B_n}}}\sum\limits_{i = 1}^n {{X_1}} \] converges in distribution N(0,1).  相似文献   

13.
Let F be a field,and let e,k be integers such that 1≤e≤|F\{0}| and k≥0.We show that for any subset{a1,…,ae}C F\{0},the curious identity∑(i1,…,ie)∈Ze≥0,i1+…+ie=kai11…aiee=e∑i=1ak+e-1i/e∏i≠j=1((ai-aj))holds with Z≥0 being the set of nonnegative integers.As an application,we prove that for any subset{a1,…,ae}? Fq\{0}with Fq being the finite field of q elements and e,l being integers such that 2≤e≤q-1 and 0≤l≤e-2,∑(i1,…,ie)∈Ze≥0,i1+…+ie=q-e+lai11…aiee=0.Using this identity and providing an extension of the principle of cross-classification that slightly generalizes the one obtained by Hong in 1996,we show that if r is an integer with 1≤r≤q-2,then for any subset{a1,…,ar}? F* we have xq-1-1/r∏i=1(x-ai)=q-1-r∑i=0(∑i1+…+ir=q-1-r-iai11…airr)xi.This implies#{x ∈ F*q | ∑q-1-ri=0(∑i1+…+ir=q-1-r-iai11…airr)xi=0}=q-1-r.  相似文献   

14.
Let X_1,…,X_n be a sequence of independent identically distributed random variableswith distribution function F and density function f.The X_are censored on the right byY_i,where the Y_i are i.i.d.r.v.s with distribution function G and also independent of theX_i.One only observesLet S=1-F be survival function and S be the Kaplan-Meier estimator,i.e.,where Z_are the order statistics of Z_i and δ_((i))are the corresponping censoring indicatorfunctions.Define the density estimator of X_i by where =1-and h_n(>0)↓0.  相似文献   

15.
设A∈C~(m×n),B∈C~(m×p)及四个矩阵方程:1)AGA=A,2)GAG=G,3)(AG)~*=AG,4)(GA)~*=GA如果G满足上述方程i),j),…k),则称G为(ij…k)型逆或penrose型广义逆,简称广义逆,并记为A(ij…k).其全体记为A{ij…k},利用矩阵广义逆的理论研究了下列两类等式成立的的充要条件:I)其中α+β=1,α>0,β>0,1≤i相似文献   

16.
The generalized product bi-conjugate gradient(GPBiCG(m,l))method has been recently proposed as a hybrid variant of the GPBi CG and the Bi CGSTAB methods to solve the linear system Ax=b with non-symmetric coefficient matrix,and its attractive convergence behavior has been authenticated in many numerical experiments.By means of the Kronecker product and the vectorization operator,this paper aims to develop the GPBi CG(m,l)method to solve the general matrix equation■ and the general discrete-time periodic matrix equations■ which include the well-known Lyapunov,Stein,and Sylvester matrix equations that arise in a wide variety of applications in engineering,communications and scientific computations.The accuracy and efficiency of the extended GPBi CG(m,l)method assessed against some existing iterative methods are illustrated by several numerical experiments.  相似文献   

17.
In this paper, we concern the divergence Kohn-Laplace equation$$\sum\limits_{i = 1}^n {\sum\limits_{j = 1}^n {\left( {X_j^*({a^{ij}}{X_i}u) + Y_j^*({b^{ij}}{Y_i}u)} \right)} } + Tu = f - \sum\limits_{i = 1}^n {\left( {X_i^*{f^i} + Y_i^*{g^i}} \right)}$$ with bounded coefficients on the Heisenberg group ${{\mathbb{H}}^n}$, where ${X_1}, \cdots, {X_n},{Y_1}, \cdots, {Y_n}$ and $T$ are real smooth vector fields defined in a bounded region $\Omega \subset {\mathbb{H}^n}$. The local maximum principle of weak solutions to the equation is established. The oscillation properties of the weak solutions are studied and then the Hölder regularity and weak Harnack inequality of the weak solutions are proved.  相似文献   

18.
In this paper, we study the case of independent sums in multi-risk model. Assume that there exist k types of variables. The ith are denoted by {Xij, j ≥ 1}, which are i.i.d.with common density function fi(x) ∈ OR and finite mean, i = 1,..., k. We investigate local large deviations for partial sums k i=1Sni= k i=1 nij=1Xij.  相似文献   

19.
关于正定厄米特矩阵的一个不等式的推广   总被引:2,自引:0,他引:2  
本文推广了正定厄米特矩阵的一个不等式 ,得到以下结果 :设 A( i) ,B( i) ,… ,C( i) ( i=1 ,2 ,… ,m)都是 n阶正定厄米特矩阵 ,A( i)11,B( i)11,… ,C( i)11为其相应矩阵的 k阶顺序主子阵 ,1≤ k≤ n-1 ,α,β,… ,γ都是正实数 ,且 α+β+… +γ=p≥ 1 ,则有∑mi=1|A( i) |α|A( i)11|α,|B( i) |β|B( i)11|β… |C( i) |γ|C( i)11|γ) <∑mi=1A( i) α∑mi=1A( i)11α.∑mi=1B( i) β∑mi=1B( i)11β…∑mi=1C( i) γ∑mi=1C( i)11γ  相似文献   

20.
证明了一类n阶(n=P_1P_2…p_m,p_i(i=1,2,…,m)互异为素数)环是有限循环环,并讨论了他们的结构及相关性质,最后给出了这类n阶环有零因子或有子域的充要条件.主要结果:P_1P_2…P_m阶环共有2m个,它们是(p_(1m个,它们是(p_(1k_1) p_(2k_1) p_(2k_2)…p_(mk_2)…p_(mk_m)Z)/(p_(1k_m)Z)/(p_(1k_1+1)p_(2k_1+1)p_(2k_2+1)…p_(mk_2+1)…p_(mk_m+1)Z),其中k_i=0或1,1≤i≤m;阶是n=P_1P_2…p_m的环R可唯一分解为m个素数阶理想的直和,即R=〈α〉=(?);含pi(1≤i≤m)阶子域的P_1P_2…P_m阶环共有2k_m+1)Z),其中k_i=0或1,1≤i≤m;阶是n=P_1P_2…p_m的环R可唯一分解为m个素数阶理想的直和,即R=〈α〉=(?);含pi(1≤i≤m)阶子域的P_1P_2…P_m阶环共有2(m-1)个,它们是p_(1(m-1)个,它们是p_(1k_1) p_(2k_1) p_(2k_2)…p_(mk_2)…p_(mk_m)Z)/(p_(1k_m)Z)/(p_(1k_1+1)p_(2k_1+1)p_(2k_2+1)…p_(mk_2+1)…p_(mk_m+1)Z),其.中k_i=0,k_j=0或1,1≤j≤m,j≠i.  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