关于循环环的理想、素理想和极大理想

研究了循环环R=的理想、素理想和极大理想的个数和结构,得到了如下结论:1)理想:(1)若|R|=∞,则R共有无穷多个理想:;(2)若|R|=n,设n的正因数个数为T(n),则R共有T(n)个理想:.2)素理想:(1)若|R|=∞,设a^2=ka(k≥0),①当k=0时,R的素理想只有R;②当k>0时,R的素理想共有无穷多个,它们是:{0}、R及;(2)若|R|=n>1,设a^2=ka,0≤k.3)极大理想:(1)若|R|=∞,则R有无限多个极大理想,它们是;(2)若|R|=n>1,设n的互不相同的素因数个数为ψ(n),则R共有ψ(n)个极大理想:(pa|p是n的素因数).     

单状态变量的局部对称性分岔问题中内蕴子模的一点注记

本文证明了Itr(^→T，Z2)=(ItrT)．{x}当且仅当ItrT由T中所有单项式生成，这里T是εu，λ中的理想且T=T．{x}在^→εx，λ(Z2)中具有有限Z2余维数，此结果表明，Golubitsky的书中关于最大内蕴理想和最大内蕴子模的关系式是错误的，本文最后给出了反例。     

幂格的理想与素理想

研究了幂格的理想和素理想,建立了格的理想与格上幂格的理想的一种联系,获得了格的理想(素理想)与它的商格的理想(素理想)之间的关系。     

半群的(∈,∈∨q(λ,μ))-模糊n伪理想与Drazin半群的刻画

给出半群的模糊n伪理想,广义模糊n伪理想,(∈,∈∨q(λ,μ))-模糊n伪理想的定义,同时讨论了(∈,∈∨q(λ,μ))-模糊n伪左理想(右理想,理想)和广义模糊n伪左理想(右理想,理想)的等价刻画.还利用半群的广义模糊子系统来刻画Drazin半群的结构.     

序半群中的粗糙理想

引入了序半群中(上,下)粗糙理想的概念,讨论了序半群中理想与(上,下)粗糙理想的关系,证明了对含最小元的序半群,若任一元素的等价类是有限的,则下粗糙理想之集关于包含序构成一个代数格。最后,讨论了(半,准)素理想与(上,下)粗糙(半,准)素理想的关系。     

因子中原子CSL代数的Lie理想

设B是带有Cartan子代数D的因子,T(L)是B中的原子CLS代数．本文讨论了T(L)中的Lie理想的结构．证明了T(L)中的σ-弱闭子空间L是T(L)的一个Lie理想当且仅当存在T(L)的一个σ-弱闭的结合理想J和T(L)的对角部分的中心的一个子空间E使得(J)~0■L■J E,其中J~0是J中迹为0的元的全体．     

BCI代数的软关联理想和软正定关联理想

给出BCI代数的软关联理想和软正定关联理想的概念,讨论软理想、软关联理想和软正定关联理想三者之间的关系,研究了两个软关联理想(软正定关联理想)的扩展交、限制交、限制并和限制差分的性质。     

亚BCI-代数的模糊理想

引入了亚BCI-代数的模糊子代数、模糊理想、闭模糊理想和模糊P-理想的概念,研究了它们的性质。证明了模糊子代数(模糊理想、闭模糊理想、模糊P-理想)的同态像与同态原像仍能成为模糊子代数(模糊理想、闭模糊理想、模糊P-理想)。     

侧完备Riesz空间中理想的直和及其表示定理

设{Ei：i∈I)是侧完备Riesz空间E中的一族理想，且Ei∩Ej=θ(i，j∈I，i≠j)．文章引入理想族{Ei：i∈I)直和的概念，并给出一个表示定理．文章证明了：存在一个完备的正则Hausdorff空间X使得理想族的直和Riesz同构于C(X)其充要条件是对每个i∈I存在一个紧Hausdorff空间Xi使得Ei Riesz同构于C(X)．     

理想簇和根理想

关于环的理想的根有两种定义,一种是所有包含I的极大理想的交,另一种是所有包含I的素理想交,本文主要研究后者定义的一些性质,以及和理想簇V(I)(所有包含I的素理想的集合)的关系.     

两物种超过程的构造

本文利用Ｄｙｎｋｉｎ的分枝粒子系统的方法，通过对两物种分枝粒子系统规整取极限，构造了一类广泛的两物种超过程，并研究了这类超过程的可加泛函的性质。     

The buy price in auctions with discrete type distributions

This paper considers second-price, sealed-bid auctions with a buy price where bidders’ types are discretely distributed. We characterize all equilibria in which bidders whose types are less than the buy price bid their own valuations. Budish and Takeyama (2001) analyze the two-bidder, two-type framework. They show that if bidders are risk-averse, then the seller can obtain a higher expected revenue from the auction with a certain buy price than from the auction without a buy price. We extend their revenue improvement result to the n-bidder, two-type framework. In case of three or more types, however, bidders’ risk aversion is not a sufficient condition for a revenue improvement. We point out that even if bidders are risk-averse, the seller cannot always obtain a higher expected revenue from the auctions with a buy price.     

具有混合保费收入的双险种二项风险模型

将双二项风险模型推广为具有混合保费收入的新模型,并运用鞅论的方法得出破产概率满足Lundberg不等式和一般表达式.     

Stochastic equations for two-type continuous-state branching processes with immigration and competition

A class of two-type continuous-state branching processes with immigration and competition is constructed as the solution of a jump-type stochastic integral equation system. We first show that the stochastic equation system has a pathwise unique non-negative strong solution and then prove the comparison property of the solution.     

一类广义离散双险种风险模型

本推广了[1]中的离散双险种风险模型，讨论了保单到达过程为Poisson随机序列时的情况，得到了最终破产概率的Lundberg不等式以及一般表达式。     

Stochastic equations for two-type continuous-state branching processes with immigration

A two-dimensional stochastic integral equation system with jumps is studied. We first prove its unique weak solution is a two-type continuous-state branching process with immigration. Then the comparison property of the solution is established. These results imply the existence and uniqueness of the strong solution of the stochastic equation system.     

Diffusion approximation of the two-type Galton-Watson process with mean matrix close to the identity

In this paper a diffusion approximation to the two-type Galton-Watson branching processes with mean matrix close to the identity is given in the form of Berstein stochastic differentials. An associated diffusion equation is found using an extension of the one-dimensional Bernstein technique. Expressions for the mean vector and covariance matrix of the diffusion approximation are derived.     

Stochastic equations and ergodicity for two-type continuous-state branching processes with immigration in Lévy random environments

This paper establishes a stochastic differential equation system with both positive and negative jumps and proves the existence and uniqueness of the strong solution and presents an equivalent condition for ergodicity of the solution. The strong solution is called two-type continuous-state branching processes with immigration in Lévy random environments. The model can be extended to any finite dimensional case.     

A class of two-type point processes

Summary A construction is given of a class of two-type point processes with Poisson marginals but possibly negative correlation between points of different types. Examples of the construction are given. The correlation structure of the processes is determined, and criteria obtained for the processes to be stationary, ergodic and mixing.Research supported by Social Science Research Council Spatial Data Project     

Parameter estimation in two-type continuous-state branching processes with immigration

We study the parameter estimation of two-type continuous-state branching processes with immigration based on low frequency observations at equidistant time points. The ergodicity of the processes is proved. The estimators are based on the minimization of a sum of squared deviation about conditional expectations. We also establish the strong consistency and central limit theorems of the conditional least squares estimators and the weighted conditional least squares estimators of the drift and diffusion coefficients based on low frequency observations.