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971.
Let ? be a class of groups and G a finite group. We call a set Σ of subgroups of G a G-covering subgroup system for ? if G ∈ ? whenever Σ ? ?. For a non-identity subgroup H of G, we put Σ H be some set of subgroups of G which contains at least one supplement in G of each maximal subgroup of H. Let p ≠ q be primes dividing |G|, P, and Q be non-identity a p-subgroup and a q-subgroup of G, respectively. We prove that Σ P and Σ P ∪ Σ Q are G-covering subgroup systems for many classes of finite groups. 相似文献
972.
In this paper, we introduce the fundamental notions of closure operator and closure system in the framework of quantaloid-enriched category. We mainly discuss the relationship between closure operators and adjunctions and establish the one-to-one correspondence between closure operators and closure systems on quantaloid-enriched categories. 相似文献
973.
考虑速度和温度同时在加法白噪声扰动下的随机Boussinesq方程组的解的渐近特征.可以接轨道得到该随机方程组的唯一解,并可以验证该解生成随机动力系统,进而证明了该随机动力系统存在随机吸引子. 相似文献
974.
《偏微分方程通讯》2013,38(1-2):409-438
Abstract We study the asymptotic behavior of solutions of the Cauchy problem for a functional partial differential equation with a small parameter as the parameter tends to zero. We establish a convergence theorem in which the limit problem is identified with the Cauchy problem for a nonlinear parabolic partial differential equation. We also present comparison and existence results for the Cauchy problem for the functional partial differential equation and the limit problem. 相似文献
975.
This paper is focused on global exponential stability of certain switched systems with time-varying delays. By using an average dwell time (ADT) approach that is different from the method in [P.H.A. Ngoc, On exponential stability of nonlinear differential systems with time-varying delay, Applied Mathematics Letters 25 (2012) 1208–1213], we establish a new global exponential stability criterion for the switched linear time-delay system under the ADT switching. We also apply this method to a general switched nonlinear time-delay system. A numerical example is given to show the effectiveness of our results. 相似文献
976.
977.
Annette Pilkington 《代数通讯》2013,41(5):1965-1993
A complete lattice structure is defined on the underlying set of the orthogonal group of a real Euclidean space, by a construction analogous to that of the weak order of Coxeter systems in terms of root systems. This produces a complete rootoid in the sense of Dyer, with the orthogonal group as underlying group. It is shown that this complete lattice has a saturation property which is used along with other properties of the lattice to characterize the maximal totally ordered subsets of the lattice as collections of initial sections with respect to a total ordering on the positive roots. 相似文献
978.
F. Wehrung 《代数通讯》2013,41(12):5893-5919
We extend the usual definition of coherence, for modules over rings, to partially ordered right modules over a large class of partially ordered rings, called po-rings. In this situation, coherence is equivalent to saying that solution sets of finite systems of inequalities are finitely generated semimodules. Coherence for ordered rings and modules, which we call po-coherence, has the following features:. (i) Every subring of Q, and every totally ordered division ring, is po-coherent. (ii) For a partially ordered right module Aover a po-coherent poring R Ais po-coherent if and only if Ais a finitely presented .R-module and A +is a finitely generated R +-semimodule. (iii) Every finitely po-presented partially ordered right module over a right po-coherent po-ring is po-coherent. (iv) Every finitely po-presented abelian lattice-ordered group is po-coherent. 相似文献
979.
研究了同时考虑节能减排效益和经济效益时,风火电联合上网的决策模型,并采用提出的KKT框架下的量子遗传算法进行模型的求解。综合考虑风电和火电的特点,建立经济效益函数和节能减排效益函数以及相关的约束条件,最终确立多目标决策模型。在KKT框架下将多目标函数转化为单目标,并利用量子遗传算法进行模型的求解。算例分析显示本文提出的KKT框架下的量子遗传算法在决策模型的求解时能够利用更少的CPU运行时间获得更优的决策结果,与其他常用的优化模型相比具有较高的优越性。 相似文献
980.