ON THE ASYMPTOTIC BEHAVIOR OF THE INTERMEDIATE POINT IN THE HIGHER-ORDER LAGRANGE MEAN VALUE THEOREM

In 1982,Bernar Jacobson [2] proved that in the Mean Value Theorem forIntegrals,integral from 0 to x f(t)dt=f(c)(x-α),as x approaches α,the intermediate point capproaches the midpoint between a and x,i.e.(?)[(c-α)/(x-α)]=1/2.In the meantime,Alfonso G.Azpeitia established the analogous result for theTaylor Formula [1].Recently,Li Wenrong studied the asymptotic behavior ofthe intermediate points in the Cauchy Mean Value Theorem and the Generali-     

GAMMA-MINIMAX ESTIMATORS FOR THE MEAN VECTOR OF A MULTIVARIATE NORMAL DISTRIBUTION

Γ-minimax estimators are determined for the mean vector of a multivariate normaldistribution under arbitrary squared error loss.Thereby the set Γ consists of all priorswhose vector of first moments and matrix of second moments satisfy some given restric-tions.Necessary and sufficient conditions are derived which ensure a prior being leastfavourable in Γ and the unique Bayes estimator with respect to this prior being Γ-minimax.By applying these results the Γ-minimax estimator is explicitly found in some special casesor can be computed by solving a system of non-linear equations or by minimizing a quad-ratic form on a compact and convex set.     

A KERNEL-TYPE ESTIMATOR OF A QUANTILE FUNCTION UNDER RANDOMLY TRUNCATED DATA

A kernel-type estimator of the quantile function Q(p) = inf {t : F(t)≥p}, 0≤p≤1, is proposed based on the kernel smoother when the data are subjected to random truncation. The Bahadur-type representations of the kernel smooth estimator are established, and from Bahadur representations the authors can show that this estimator is strongly consistent, asymptotically normal, and weakly convergent.     

ON ABELIAN AUTOMORPHISM GROUPS OF SURFACES OF GENERAL TYPE

1.IntroductionItiswell-knownthatforacomplexcurveofgenusg22,itstotalautomorphismgroup(resp.abelianautomorphismgroup)isoforderS84(g-l)=42degKC(resp.S4g 4),whereKCisthecanonicaldivisorofC(cL[3,4]).Itisanintriguingproblemtogeneralisetheseboundstohigherdimensions.Severalauthorshavestudiedthisproblem(see[5,6]fordetails).Recently,Xiaohasgeneralisedtheseresultstosurfacesofgeneraltype,ingoodanalogywiththecaseofcurves.HehasprovedthatforacomplexminimalsmoothprojectivesurfaceSofgeneraltype,itstota1au…     

ON LIMITING PROPERTIES OF BERNSTEIN-TROTTER TYPE OPERATOR

In this paper ,a class of Bernstein-Trotter type operator and its limiting properties are studied. By using both the limiting theorem and P. Le‘ vy continuity theorem on probability theory, a theorem of convergence is obtained. The result in [1] is included.     

ON THE BOREL SUBGROUPS OF LARGE TYPE

The author defines the large type Borel subgroups of a reductive algebraic group, which are used to discuss Langlands' L-groups and the Langlands classification of the admissible representations of reductive algebraic groups over R (see [1, 2, 5])and determine all of the Borel subgroups of large type for the classical semisimple Lie groups.     

GAMMA－MINIMAX ESTIMATORS FOR THE MEAN OF A MULTIVARIATE NORMAL DISTRIBUTION WITH PARTIALLY UNKNOWN COVARIANCE MATRIX

ＧＡＭＭＡ－ＭＩＮＩＭＡＸＥＳＴＩＭＡＴＯＲＳＦＯＲＴＨＥＭＥＡＮＯＦＡＭＵＬＴＩＶＡＲＩＡＴＥＮＯＲＭＡＬＤＩＳＴＲＩＢＵＴＩＯＮＷＩＴＨＰＡＲＴＩＡＬＬＹＵＮＫＮＯＷＮＣＯＶＡＲＩＡＮＣＥＭＡＴＲＩＸＣＨＥＮＬＡＮＸＩＮＧ（陈兰祥）（Ｄｅｐａｒｔ...     

ON GLOBAL SOLUTION FOR A CLASS OF SYSTEMS OF MULTI－DIMENSIONAL GENERALIZED ZAKHAROV TYPE EQUATION

ＯＮＧＬＯＢＡＬＳＯＬＵＴＩＯＮＦＯＲＡＣＬＡＳＳＯＦＳＹＳＴＥＭＳＯＦＭＵＬＴＩ－ＤＩＭＥＮＳＩＯＮＡＬＧＥＮＥＲＡＬＩＺＥＤＺＡＫＨＡＲＯＶＴＹＰＥＥＱＵＡＴＩＯＮＧＵＯＢＯＬＩＮＧ（郭柏灵）（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄａｎｄＣｏｍｐｕ...     

STUDY ON THE INTERRELATION OF EFFICIENT PORTFOLIOS AND THEIR FRONTIER UNDER t DISTRIBUTION AND VARIOUS RISK MEASUREgS

In order to study the effect of different risk measures on the efficient portfolios （fron- tier） while properly describing the characteristic of return distributions in the stock market, it is assumed in this paper that the joint return distribution of risky assets obeys the multivariate t-distribution. Under the mean-risk analysis framework, the interrelationship of efficient portfolios （frontier） based on risk measures such as variance, value at risk （VaR）, and expected shortfall （ES） is analyzed and compared. It is proved that, when there is no riskless asset in the market, the efficient frontier under VaR or ES is a subset of the mean-variance （MV） efficient frontier, and the efficient portfolios under VaR or ES are also MV efficient; when there exists a riskless asset in the market, a portfolio is MV efficient if and only if it is a VaR or ES efficient portfolio. The obtained results generalize relevant conclusions about investment theory, and can better guide investors to make their investment decision.     

STUDY ON THE INTERRELATION OF EFFICIENT PORTFOLIOS AND THEIR FRONTIER UNDER t DISTRIBUTION AND VARIOUS RISK MEASURES

In order to study the effect of different risk measures on the efficient portfolios (frontier) while properly describing the characteristic of return distributions in the stock market, it is assumed in this paper that the joint return distribution of risky assets obeys the multivari-ate t-distribution. Under the mean-risk analysis framework, the interrelationship of efficient portfolios (frontier) based on risk measures such as variance, value at risk (VaR), and expected shortfall (ES) is analyzed and compared. It is proved that, when there is no riskless asset in the market, the efficient frontier under VaR or ES is a subset of the mean-variance (MV) efficient frontier, and the efficient portfolios under VaR or ES are also MV efficient; when there exists a riskless asset in the market, a portfolio is MV efficient if and only if it is a VaR or ES efficient portfolio. The obtained results generalize relevant conclusions about investment theory, and can better guide investors to make their investment decision.     

非正则双边截断分布族点估计的中偏差

本文研究了某一类非正则双边截断分布族的参数估计,利用( X(1),X(n))的联合分布函数及应用Taylor渐近展开的方法,得到了它的未知参数(θ1,θ2)满足中偏差原理,且求出了其精确的速率函数表达式,它的表达式不同于一般的速率函数.     

截断参数分布族参数的可容许估计

在平方损失下Karlin[1]讨论了截断参数分布族参数的可容许估计问题．本文讨论了当待估参数为单调函数和多项式函数时的可容许估计问题.文[1]讨论的待估参数，形式上较特殊，有关结果可视为本文结论的一个特例．     

截断与删失数据的极大似然估计的中偏差

本文研究了截断与删失模型,运用Taylor渐近展开方法,得到模型的极大似然估计的中偏差,比渐近正态性结果更加精细.     

半参数回归模型的渐近有效L-估计

对半参数回归模型yi=χiTβ+g(χi)+ei,i=1,2,…,n,对非参数函数g(·)采用核估计的方法,构造了参数向量β的L-估计量λn,在一些正则条件下,获得了λn的渐近正态性和非参数函数g(·)的估计量gn(t)的最优收敛速度可达到O(n-(1/3)),并且给出了标准化L估计量λn的渐近分布的Berry-Esseen界.     

左截断右删失数据下半参数模型风险率函数估计

文章给出了右删失左截断数据半参数模型下的风险率函数估计,讨论了风险率函数估计的渐近性质,获得了这些估计的渐近正态性,对数律和重对数律.由于假定删失机制服从半参数模型下,从而知道模型的更多信息,因此对于给出参数的极大似然估计,可以改进风险率函数估计的渐近性质.也就是说,删失数据模型具有半参数的辅助信息下, 风险率函数估计的渐近方差比通常的完全非参数的估计的渐近方差更小.这说明加入了额外的信息提高了风险率函数估计的效率.     

GBVE分布相关参数的矩型估计

考虑Gumbel提出的二元指数分布,其可靠度函数为 .我们把这类分布称为 .根据(Lnx1,LnX2)的混合矩的性质,本文提出了δ的两个矩型估计δ1和δ2,证明了δ1和δ2都有强相合性和渐近正态性,得到了δ1和δ2的渐近方差σδ12和σδ22并把σδ12和σδ22作了比较.最后还给出了若干随机模拟结果.     

左截断右删失下一类泛函估计的渐近性质

在左截断右删失下,本文讨论了一类广义Von－Mises泛函估计的渐近性质．在一定条件下,得到了此类泛函估计的强逼近和U-统计量表示,并由此得出它的强相合性、渐近正态性及重对数律．     

删失数据半参数回归模型的样条估计量的渐近正态性

本文研究了删失数据半参数回归模型的渐近正态性问题.利用样条光顺和合成数据的方法,获得了参数β、非参数h(t)的样条估计量,以及参数估计量的渐近正态性,推广了完全数据情形的相应结果[4].     

BAHADUR ASYMPTOTIC EFFICIENCY IN A SEMIPARAMETRIC REGRESSION MODEL

ＢＡＨＡＤＵＲＡＳＹＭＰＴＯＴＩＣＥＦＦＩＣＩＥＮＣＹＩＮＡＳＥＭＩＰＡＲＡＭＥＴＲＩＣＲＥＧＲＥＳＳＩＯＮＭＯＤＥＬ￥ＬＩＡＮＧＨＵＡ；ＣＨＥＮＧＰＩＮＧＡｂｓｔｒａｃｔ：ＴｈｅａｕｔｈｏｒＳｇｉｖｅＭＬＥθ１ＭＬｏｆθ１ｉｎｔｈｅｍｏｄｅｌＹ＝θ...     

回归系数Pitman估计的优良性(Ⅱ)

对线性回归模型Ｙ＝Ｘβ＋ε，证明了回归系数β的Ｐｉｔｍａｎ估计的渐近有效性，并推广了Ｐｏｒｔ和Ｓｔｏｎｅ［５］关于位移参数的有关结果，去掉了及文［４］中所施加的矩限制．