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171.
172.
Let R *θG be the skew group ring with a F.C group G and the group homom-rphismθfrom G to Aut(R), the group of automorphisms of the ring R. In this paper,the necessary and sufficient condition such that R*θG will be Noetherian is given, which generalizes the results of I.G. connel. 相似文献
173.
This article gives characterizations of generalized derivations with skew nilpotent values on noncommutative Lie ideals of a prime ring. The results simultaneously generalize the ones of Herstein, Lee and Carini et al. 相似文献
174.
Oleg Burdakov Anders Grimvall Oleg Sysoev 《计算数学(英文版)》2006,24(6):771-790
Monotonic regression (MR) is a least distance problem with monotonicity constraints induced by a partiaily ordered data set of observations. In our recent publication [In Ser. Nonconvex Optimization and Its Applications, Springer-Verlag, (2006) 83, pp. 25-33], the Pool-Adjazent-Violators algorithm (PAV) was generalized from completely to partially ordered data sets (posets). The new algorithm, called CPAV, is characterized by the very low computational complexity, which is of second order in the number of observations. It treats the observations in a consecutive order, and it can follow any arbitrarily chosen topological order of the poset of observations. The CPAV algorithm produces a sufficiently accurate solution to the MR problem, but the accuracy depends on the chosen topological order. Here we prove that there exists a topological order for which the resulted CPAV solution is optimal. Furthermore, we present results of extensive numerical experiments, from which we draw conclusions about the most and the least preferable topological orders. 相似文献
175.
Jian Zhong PAN Shao Bing WU 《数学学报(英文版)》2006,22(1):23-26
in this note, we answer positively a question by Belegradek and Kapovitch about the relation between rational homotopy theory and a problem in Riemannian geometry which asks that total spaces of which vector bundles over compact non-negative curved manifolds admit (complete) metrics with non-negative curvature. 相似文献
176.
在城市中,消防、医疗、警务等应急车辆的配置是城市管理的一个重要方面.对该问题进行了研究,提出了对其评价的两个标准:公平与效率.作者根据这两个标准建立数学模型,该模型可用于这类车辆的管理. 相似文献
177.
178.
Liu Kaiyu Wang Zhicheng 《Annals of Differential Equations》2005,21(3):343-348
This paper is concerned with a delay difference system. Some interesting results are obtained for the asymptotic behaviors of the system. Our theorems improve the corresponding theorems in the relevant literature by removing the restriction of the initial conditions. 相似文献
179.
CHO Min-hyung 《数学季刊》2005,20(2):137-140
The classical countable summation type Hahn-Schur theorem is a famous result in summation theory and measure theory. An interesting problem is whether the theorem can be generalized to non-countable summation case? In this paper, we show that the answer is true. 相似文献
180.
An associative ring with identity R is called Armendariz if, whenever (∑^m i=0^aix^i)(∑^n j=0^bjx^j)=0 in R[x],aibj=0 for all i and j. An associative ring with identity is called reduced if it has no non-zero nilpotent elements. In this paper, we define a general reduced ring (with or without identity) and a general Armendariz ring (with or without identity), and identify a class of maximal general Armendariz subrings of matrix rings over general reduced rings. 相似文献