Dyon—Fermion系统束缚态能级的具体计算

本文详细计算和讨论了荷电费米子与固定狄拉克双荷子(Dyon-Fermion)相互作用系统的束缚能量,给出了最低角动量j=|q|-1/2≥0和总角动量j≥|q|+1/2的全部能级的具体表达式。     

PM—空间中序结构及不动点定理

本文在概率度量空间(X,F)中引入半序结构“≤”、讨论了(X,≤)成为半序空间的条件,并证明了几个不动点定理。     

拓扑空间内有上下界的拟平衡问题

利用作者的一个不动点定理,在非紧拓扑空间内对具有上下界的拟平衡问题证明了解的存在性定理.这些结果进一步回答了由Isac, Sehgal和Singh提出的公开问题和推广了文献中很多重要结果.     

一类新型概率线性赋范空间及其不动点定理

本文引进了一类新型概率线性赋范空间——概率性赋范商空间,在(E~*,F~*)中由其概率范数引进一种新的距离D~*以及与D~*有关的一系列分析概念。在新的空间中得到了几个新的不动点定理,尤其是对于新的压缩型映象列{T_n},如果T_n是D~*-收敛于T,则T有不动点,且T_n的不动点构成的点列收敛于T的不动点。     

固定点控抛物型方程的整体近似能控与有限维精确能控性

研究固定点控抛物型方程：ay(t,x)/at=△y-q(x)y(t,x) ∑k=1^N vk(t)δ（x-x^K)。证明了当特征值，特征函数及控制支撑点满足某些条件时系统的整体近似能控与有限维精确能控性。     

Should fixed coefficients be re-estimated every period for extrapolation?

This paper demonstrates that forecast accuracy is not necessarily improved when fixed-coefficient models are sequentially re-estimated and used for prediction, after updating the database with the latest observation(s). It is argued that although sequential estimation may minimize the variances of predictors based on some classes of estimators, sequential estimation does not necessarily yield accurate predictions (i.e. predictions that are close to actual realizations). Minimizing the mean squared prediction error about the actual realization is a necessary condition for maximizing the probability that one predictor is more accurate than others. This minimization need not require, and may even exclude, the most recent data. It has been shown by an example that a prediction based on a nonsequential estimate of a stochastically varying coefficient model is superior to predictions based on several sequential estimates of the fixed-coefficient models, including a random walk model.     

Positive Solutions of Four-order Dierence Equations with Two Point Boundary Value Problems

Positive solutions of fourth-order dierential equations withtwo point boundary value problems are investigatedin[4,6].Inthis paper we investigate a similar problemfor dierence equations.Wedenote byZthe set of all natural numbers.Fora,b∈Z,a相似文献   

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研究了一类压缩型映射,得到其不动点的存在性定理,所得结果推广了文[1]中相应的结论。     

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