矩阵环的半交换子环

称环R是半交换的,如果对任意a∈R,rR(a)是R的理想．若n≥2,则任意具有单位元的环R上的n阶上三角矩阵环不是半交换环．我们证明了reduced环上的上三角矩阵环的一类特殊子环是半交换环．     

赋值环上的Hermite环猜想北大核心CSCD

本文主要研究赋值环上的Hermite环猜想.根据赋值环V上一元多项式环V[x]的性质,研究并得到V[x]上幺模行向量(a_(1)(x),a_(2)(x),…,a_(n)(x))的一系列关于等价的性质,进而证明了赋值环上的Hermite环猜想成立,即对任意的赋值环V,V[x]都是Hermite环.     

Ⅱ-凝聚环中的对偶性

通过π-凝聚环上的f.g.模的自反性引进了WQF-环和GIF-环,给出了QF-环一个新的刻画.并研究了π-凝聚环上的Wn模上的自反性的特征性质.     

π-凝聚环中的对偶性

通过π -凝聚环上的f.g .模的自反性引进了WQF -环和GIF -环 ,给出了QF -环一个新的刻画 .并研究了π -凝聚环上的Wn 模上的自反性的特征性质 .     

相对于幺半群的McCoy环的扩张

对于幺半群~$M$, 本文引入了~$M$-McCoy~环.~证明了~$R$~是~$M$-McCoy~环当且仅当~$R$~上的~$n$~阶上三角矩阵环~$aUT_n(R)$~是~$M$-McCoy~环;得到了若~$R$~是~McCoy~环,~$R[x]$~是~$M$-McCoy~环,则~$R[M]$~是~McCoy~环;对于包含无限循环子半群的交换可消幺半群~$M$,证明了若~$R$~是~$M$-McCoy~环,则半群环~$R[M]$~是~McCoy~环及~$R$~上的多项式环~$R[x]$~是~$M$-McCoy~环.     

Clean一般环的几个结果

证明了一般环I是Clean一般环当且仅当I上的形式幂级数一般环I[[x]]是Clean一般环;一般环I上的多项式环I[x]是Clean一般环当且仅当I是诣零的.引入了强Clean一般环的概念,它是强Clean环的推广.并证明了强π-正则的一般环是强Clean一般环.     

除环上矩阵的几个性质

该文研究了除环上的矩阵范畴，除环上n×n矩阵的柱心 幂零分解以及除环上矩阵的幂的性质     

形式三角矩阵环上的有限表示模

形式三角矩阵环,又称广义三角矩阵环,这类环及其上的模在环模理论中扮演着重要的角色.本文对形式三角矩阵环上的有限表示模进行了一些探讨.     

L-模糊环同余和L-模糊模同余

本文证明了环上的L-模糊理想和环上的L-模糊环同余关系是一一对应的,模上的L-模糊子模和模上的L-模糊模同余关系是一一对应的.     

交换环上多项式结式的性质

本文主要讨论交换环上多项式结式的一些性质.首先,我们证明了交换环上一种乘积的结式等于结式的乘积的性质,然后,我们证明了交换环上一种和的结式具有的性质,并且给出了交换环上结式为零的一个充分条件.     

A new transvectant algorithm for nilpotent normal forms

We offer an algorithm to determine the form of the normal form for a vector field with a nilpotent linear part, when the form of the normal form is known for each Jordan block of the linear part taken separately. The algorithm is based on the notion of transvectant, from classical invariant theory.     

On the Effect of Misspecifying the Density Ratio Model

The density ratio model specifies that the log-likelihood ratio of two unknown densities is of known linear form which depends on some finite dimensional parameters. The model can be broadened to allow for m-samples in a quite natural way. Estimation of both parametric and nonparametric part of the model is carried out by the method of empirical likelihood. However the assumed linear form has an impact on the estimation and testing for the parametric part. The goal of this study is to quantify the effect of choosing an incorrect linear form and its impact to inference. The issue of misspecification is addressed by embedding the unknown linear form to some parametric transformation family which yields ultimately to its identification. Simulated examples and data analysis integrate the presentation.     

On an explicit representation of the solution of linear stochastic partial differential equations with delays

Based on the analysis of a certain class of linear operators on a Banach space, we provide a closed form expression for the solutions of certain linear partial differential equations with non-autonomous input, time delays and stochastic terms, which takes the form of an infinite series expansion.     

A direct proof of theorem on generalized Jordan form of linear operators

The present paper gives a direct proof of the following result: for any linear operator over arbitrary field there exists a basis in which it has a polyquasicyclic matrix, i.e. a generalized Jordan form of second kind. The polyquasicyclic form of a linear operator is uniquely determined up to the order of direct summands on the diagonal, and it is shown that the generalized Jordan form of second kind is a link that connects the classical Jordan form and the rational canonical form.     

屈服条件由应力张量的二次齐次函数与一次齐次函数之和来表达的极限分析定理

本文建立了由应力张量σ_ij的二次齐次函数与一次齐次函数的和来表达其屈服条件的刚理想塑性体的极限分析变分原理,它可用于岩土力学的极限分析问题,并把屈服条件为应力张量σ_ij 的二次齐次函数或一次齐次函数来表达的情况作为其特例.     

Synthesis of linear systems with desired equivalent form

A method for feedback synthesis of linear control systems with desired linearly equivalent form of the closed loop system matrix is proposed. The method is based on the serial canonical form of linear multivariable systems which is an alternative to the Luenberger canonical form. A stable computational algorithm for finding the serial canonical form using orthogonal similarity transformations is described. The algorithm for synthesis involves a simple recurrent procedure and gives the possibility to achieve any attainable equivalent form of the closed loop system. The results obtained are extended to the synthesis of reduced order state observers.     

Semi-parametric estimation for the Box-Cox transformation model with partially linear structure

The Box-Cox transformation model has been widely used in applied econometrics, positive accounting, positive finance and statistics. There is a large literature on Box-Cox transformation model with linear structure. However, there is seldom seen on the discussion for such a model with partially linear structure. Considering the importance of the partially linear model, in this paper, a relatively simple semi-parametric estimation procedure is proposed for the Box-Cox transformation model without presuming the linear functional form and without specifying any parametric form of the disturbance, which largely reduces the risk of model misspecification. We show that the proposed estimator is consistent and asymptotically normally distributed. Its covariance matrix is also in a closed form, which can be easily estimated. Finally, a simulation study is conducted to see the finite sample performance of our estimator.     

Optimality conditions and strong duality in abstract and continuous-time linear programming

In this work, optimality conditions for infinite-dimensional linear programs are considered. Strong duality as an optimality condition is investigated. A new approach to duality in the form of positive extendability of linear functionals is proposed. A necessary and sufficient condition for duality in the form of a boundedness test of a related linear program is developed. Elaborating on the continuous time framework, counter cases where duality is not valid are given. In lieu of duality, other generalized duality conditions are proposed for the purpose of testing the optimality of a solution.     

买方抗衡势力对上游企业定价形式决策的影响——基于讨价还价博弈的分析

基于上游垄断、下游双寡头竞争的纵向市场结构,在讨价还价博弈的框架下,构建了下游零售商均无买方抗衡势力和单个零售商具有买方抗衡势力两种情况下的,上游供应商最优定价形式决策模型,分析了买方抗衡势力对供应商定价形式决策的影响。研究发现:从供应商利润角度来说,当零售商均无买方抗衡势力时,两部收费制和RPM(转售价格维持)是等价的,且都优于线性定价;当单个零售商具有买方抗衡势力时,RPM优于两部收费制,同时也优于线性定价,但是两部收费制与线性定价之间的关系不确定。在此结论之上,本文还讨论了政府对RPM采用不同规制政策时,供应商最优的定价形式选择。     

Reduction of systems to a form with relative degree using dynamic output transformation

A form with the extraction of the zero dynamics is the most convenient canonical form of a linear time-independent multivariable control system. Only systems with vector relative degree can be reduced to such a form. There exist control systems that, together with any system obtained from them by a time-independent change of outputs, have no relative degree. To ensure the relative degree conditions, we suggest to use an invertible dynamic change of measured outputs of the system, which allows one to solve the problem on the reduction of a linear time-independent MIMO-system to a form with relative degree in the most general case.