Asymptotically optimal empirical bayes procedures for selecting good

Let ∏₁,…,∏_k denote k independent populations, where a random observation from population ∏ _i has a uniform distribution over the interval (0,θ _i ) and θ _i is a realization of a random variable having an unknown prior distribution G _i . Population ∏ _i is said to be a good population if θ _i ≥θ₀, where θ₀ is a given, positive number. This paper provides a sequence of empirical Bayes procedures for selecting the good populationsamong ∏₁,…,∏ _k . It is shown that these procedures are asymptotically optimal and that the order of associated convergence rates is O(n^-r/4) for some r, 0<r<2, where n is the number of accumulated past observations

at hand     

特殊多面体的笵形和同伦群

<正> 多面体的伦型鉴定问题,已经有过许多拓扑工作者的研究.J.H.C.Whitehead找到 A_n~2多面体的伦型和正则上同调环头(n=2)或正则上同调系统类(n>2)间的一一对应.他和 S.Machane 发见“三型”所对应的代数构造,于是引起(?)     

Extremal solutions of Nevanlinna-Pick problems and certain classes of inner functions

Consider a scaled Nevanlinna-Pick interpolation problem and let ∏ be the Blaschke product whose zeros are the nodes of the problem. It is proved that if ∏ belongs to a certain class of inner functions, then the extremal solutions of the problem or most of them are in the same class. Three different classical classes are considered: inner functions whose derivative is in a certain Hardy space, exponential Blaschke products and the well-known class of α-Blaschke products, for 0 < α < 1.     

When ∏ is Isomorphic to ⊕

For a category , we investigate the problem of when the coproduct ⊕ and the product functor ∏ from  ^I to  are isomorphic for a fixed set I, or, equivalently, when the two functors are Frobenius functors. We show that for an Ab category  this happens if and only if the set I is finite (and even in a much general case, if there is a morphism in  that is invertible with respect to addition). However, we show that ⊕ and ∏ are always isomorphic on a suitable subcategory of  ^I which is isomorphic to  ^I but is not a full subcategory. If  is only a preadditive category, then we give an example that shows that the two functors can be isomorphic for infinite sets I. For the module category case, we provide a different proof to display an interesting connection to the notion of Frobenius corings.     

Stirling公式的一个推广

关于n!的S tirling渐近式,无论在理论上或者实际上,都有重要应用.应用Eu ler-M aclau lrin求和公式及Γ函数的性质,推导出一般等差级数连乘积并有余项估计式的类似表达式.     

乘积∏_(k=1)~n(ak~2+bk+c)的平方性

本文证明了乘积∏_(k=1)~n(ak~2+6k+c)(f(x)=ax~2+bx+c∈Z[x]是二次不可约多项式)在n充分大时不是平方数.     

同伦群和同调群的关系及其应用

<正> 最近几年来,关于同伦群的研究,特别是球面同化群的计算有很大的进步,但是关于更一般的空间的同伦群的计算,就作者所知道的文献来说,似乎没有相应的进展,在这一方面的工作,最早也是最主要的是 Hurewicz 定理,Serre 在[15]中利用所谓 C同构的概念,把 Hurewicz 定理推广到所谓(n-1)维 C 连通空间中,但是也和 Hure-wicz 定理一样,只能讨论 n 维同伦群和 n 维同调群的关系.张素诚,Hilton 及 Barrat     

Property ∏σ and tensor products of operator algebras

In this paper, we introduce Property ∏σ of operator algebras and prove that nest subalgebras and the finite-width CSL subalgebras of arbitrary von Neumann algebras have Property ∏σ.Finally, we show that the tensor product formula alg ML1-(×)algNL2 = algM-(×)N(L1 (×) L2) holds for any two finite-width CSLs L1 and L2 in arbitrary von Neumann algebras M and N, respectively.     

Upper triangularization of matrices by permutations and lower triangular similarity transformations

Let A be an arbitary (square) matrix. As is well known, there exists an invertible matrix S such that S^-1AS is upper triangular. The present paper is concerned with the observation that S can always be chosen in the form S=∏L, where ∏ is a permutation matrix and L is lower triangular. Assuming that the eigenvalues of A are given, the matrices ∏, L, and U=L^-1∏^-1A∏L are constructed in an explicit way. The construction gives insight into the freedom one has in choosing the permutation matrix ∏. Two cases where ∏ can be chosen to be the identity matrix are discussed (A diagonable, A a low order Toeplitz matrix). There is a connection with systems theory.     

整系数多项式有理根一个新求法的再探讨

设f (x)为整系数多项式,α为有理数,对n个不同的整数t1,…,tn,gα(tk) =f (tk)tk-α都是整数,那么α是f (x)的根的充要条件是f (t) =∑ni=1∏1≤j≤nj≠it-tjti-tjgα(ti) ( t∈Z) .     

一类迭代微分方程的解析解

给出一类 n阶迭代泛函微分方程 x( n) =a∏li=1(x[mi] (qiz) ) ki的形如 x(z) =λzμ的解的存在性     

A Curious Identity on Multiple Sums over Fields with Applications

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.     

多线性分数次积分算子一般框架下的交换子的有界性——献给陆善镇教授75华诞

对任意给定的正整数m,Z^＋×{1,...,m}的任意一个有限子集S,定义一般化的多线性分数次积分算子的交换子Iα,→b,S（f）（x）=∫（Rn）^m ∏（i,j）∈S（bi（x）-bi（yj））/（｜x-y1｜＋…＋｜x-ym｜）^mn-α∏（j=1→m）fj（yj）d→y,其中d→y=dy1…dym.此框架下的交换子包含了以往研究的各类分数次积分算子的交换子,并蕴含了多线性背景下新的交换子形式.在上述非常一般框架下,本文给出带多重A→p,q权的多线性分数次积分算子的交换子Iα,→b,S（→f）的加权强型（L^p1（ω1）×···×L^pm（ωm）,L^q（ν→ωq））估计和加权弱型端点估计.本文还得到更一般核条件下的上述结果.     

Fuzzy sets as a basis for a theory of possibility

The theory of possibility described in this paper is related to the theory of fuzzy sets by defining the concept of a possibility distribution as a fuzzy restriction which acts as an elastic constraint on the values that may be assigned to a variable. More specifically, if F is a fuzzy subset of a universe of discourse U={u} which is characterized by its membership function μ_F, then a proposition of the form “X is F,” where X is a variable taking values in U, induces a possibility distribution ∏X which equates the possibility of X taking the value u to μF(u)—the compatibility of u with F. In this way, X becomes a fuzzy variable which is associated with the possibility distribution ∏_x in much the same way as a random variable is associated with a probability distribution. In general, a variable may be associated both with a possibility distribution and a probability distribution, with the weak connection between the two expressed as the possibility/probability consistency principle.A thesis advanced in this paper is that the imprecision that is intrinsic in natural languages is, in the main, possibilistic rather than probabilistic in nature. Thus, by employing the concept of a possibility distribution, a proposition, p, in a natural language may be translated into a procedure which computes the probability distribution of a set of attributes which are implied by p. Several types of conditional translation rules are discussed and, in particular, a translation rule for propositions of the form “X is F is α-possible,” where α is a number in the interval [0, 1], is formulated and illustrated by examples.     

On diagonal products of doubly stochastic matrices

The following result is proved: If A and B are distinct n × n doubly stochastic matrices, then there exists a permutation σ of {1, 2,…, n} such that ∏_ia_iσ(i) > ∏_ib_iσ(i).     

一类脉冲微分方程正周期解存在的充要条件

考虑非线性脉冲微分方程{x＇（t）=x（t）[a（t）-b（t）x^p（t）],t≠tk, △x｜t=tk=ckx（tk）,k∈N.得到了该方程存在正周期解的充要条件为m∏k=1（1＋ck）^pexp（p∫^w 0）a（σ）dσ）＞1.     

关于强J-空间与JHB-空间

引入了两个很有联系的空间类JHB-空间与强J HB-空间，分别推广了J-空间与强J-空间.讨论了J-空间、强J-空间、J HB-空间及强JHB-空间类间的相包含关系及此四空间类逆包含的条件，还得到了JHB-空间的内部刻画，并证明了若对每个α∈S，Xα.都是非紧的连通空间，则积空间∏α∈S Xα是强J-空间。     

关于Boutroux—Cartan定理的推广

推广了著名的Boutroux—Cartan定理。设aμ（μ=1，2，…，n）为复平面上任意的n个点，H为任意的一个正数，则在平面上同时使得n∏μ=1 ｜z-aμ｜≤（H/e）^n和n∑μ=1 1/｜z-aμ｜≥nlog（en）/H成立的点z可被含于总数不超过n，半径总和不超过2H的一组圈内。     

A note on characterization of Hardy space <Emphasis Type="Italic">H</Emphasis><Superscript>1</Superscript>

An all-round answer is given to the following question: "Find a necessary and sufficient size condition for an integrable compactly supported function on Rn with mean value zero to be in the Hardy space H1." Stefanov answers it only for n = 1. Equivalent answer is also given for n = 1.     

LP[0,1](1＜p＜∞)空间正系数多项式倒数逼近的一个推广

本文推广了LP[0,1](1＜p＜∞)空间函数的正系数多项式的倒数逼近的结论,即证明了:设f(x)∈LP[0,1],1＜p＜∞,且在(0,1)内严格1次变号,则存在一点x0∈(0,1)及一个n次多项式Pn(x)∈∏n(+)使得‖f(x)-x-x0/Pn(x)‖LP[0,1]≤Cpω(f,n-1/2)LP[0,1],其中∏n(+)为次数不超过n的正系数多项式的全体.