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1.
一族具有正则幺半群的图   总被引:2,自引:0,他引:2  
本文给出了一族具有正则自同态幺半群的图及相应的自同态计数公式。  相似文献   

2.
本文研究图及其强自同态幺半群.首先刻画了图的强自同态幺半群的正则元,然后给出了此幺半群正则的充要条件.这推广了[1]和[2]中关于有限图的强自同态幺半群正则的结果.  相似文献   

3.
图的完全正则自同态   总被引:1,自引:0,他引:1  
作为图的代数分析的一部分,对图的自同态幺半群的研究近年来有一定的进展(参见[3]及[4])。这类研究的主要目的在于将半群理论应用于图论。文献[5]研究了图的正则自同态及其逆。在此基础上本文进一步描述了图的完全正则自同态的组合特征;同时对含有完全正则自同态f的极大子群,文中也明确给出了其单位元素及f的逆  相似文献   

4.
图的强化缩核与图的强自同态幺半群的正则性   总被引:1,自引:0,他引:1  
本文研究图及其强自同态幺半群,首先刻画了图的强自同态幺半群的正则元,然后给出了此幺半群正则的充要条件,这推广了(1)和(2)中关于有限图的强自同态幺半群正则的结果。  相似文献   

5.
END-正则的循环图   总被引:1,自引:1,他引:0  
樊锁海  谢虹玲 《应用数学》2002,15(4):105-108
称图X是End-正则图如果它的自同态幺半解EndX是正则的幺半解,即关于任意自同态f存在一个自同态g使得fgf=f。本文对顶点度数小于4的End-正则循环图进行了刻划。  相似文献   

6.
讨论了图的广义字典序积的自同态幺半群的性质,给出了广义字典序积图X[Yz|x∈V(X)]的自同态幺半群与X,Yx(x∈V(X))的自同态幺半群的圈积相等的充要条件。  相似文献   

7.
本文给出了具有完全正则自同态半群的分裂图的结构特征.其证明方法有望应用于其他图族自同态半群的正则性及完全正则性的研究.  相似文献   

8.
图的P-正则自同态幺半群   总被引:2,自引:0,他引:2  
樊锁海 《数学杂志》2000,20(2):161-167
刻划了具有P-正则自同态幺半群的二分图,讨论了字典序积图的自同态幺半群的P-正则性。  相似文献   

9.
Jacobson在〔1,ch6〕中,给出了如下定义:M为一加群,A是{M,+}的自同态环,则M可以看成是忠实右A-模。如M是完全可约的A-模,则称A为完全可约的自同态环;如A还是齐次的,即M的所有不可约A-子模均同构,则称A是齐次完全可约的自同态环;如完全可约自同态环A在M所定义的有限拓扑中是闭的,则称A是可分辨的完全可约自同态环。  相似文献   

10.
旗流形的上同调环的自同态   总被引:2,自引:0,他引:2  
赵旭安 《数学学报》2001,44(6):1099-110
本文应用李群理论,对紧单李群G,给出了旗流形 G/T的上同调环自同态的完全分类,并对典型群计算了相应自同态的Lefschetz数.  相似文献   

11.
两类带有确定潜伏期的SEIS传染病模型的分析   总被引:2,自引:0,他引:2  
通过研究两类带有确定潜伏期的SEIS传染病模型,发现对种群的常数输入和指数输入会使疾病的传播过程产生本质的差异.对于带有常数输入的情形,找到了地方病平衡点存在及局部渐近稳定的阈值,证明了地方病平衡点存在时一定局部渐近稳定,并且疾病一致持续存在.对于带有指数输入的情形,发现地方病平衡点当潜伏期充分小时是局部渐近稳定的,当潜伏期充分大时是不稳定的.  相似文献   

12.
整环R称为ω-凝聚整环,是指R的每个有限型理想是有限表现型的.本文证明了ω-凝聚整环是v-凝聚整环,且若(RDTF,M)是Milnor方图,则在Ⅰ型情形,R是ω-凝聚整环当且仅当D和T都是ω-整环,且T_M是赋值环;对于Ⅱ-型情形,R是ω-凝聚整环当且仅当D是域,[F:D]<∞,M是R的有限型理想,T是ω-凝聚整环,且R_M是凝聚整环.  相似文献   

13.
A general framework is presented in which the relation of the set of noninferior points and the set of compromise solutions is studied. It is shown that the set of compromise solutions is dense in the set of noninferior points and that each compromise solution is properly noninferior. Also, under convexity of the criteria space, a characterization of the properly noninferior points in terms of the compromise solutions is presented. In this characterization, the compromise solutions depend continuously on the weights. Use of the maximum norm is studied also. It is shown that a subset of these max-norm solutions, obtained by taking certain limits of compromise solutions, is dense and contained in the closure of the set of noninferior points.  相似文献   

14.
A set-covering problem is called regular if a cover always remains a cover when any column in it is replaced by an earlier column. From the input of the problem - the coefficient matrix of the set-covering inequalities - it is possible to check in polynomial time whether the problem is regular or can be made regular by permuting the columns. If it is, then all the minimal covers are generated in polynomial time, and one of them is an optimal solution. The algorithm also yields an explicit bound for the number of minimal covers. These results can be used to check in polynomial time whether a given set-covering problem is equivalent to some knapsack problem without additional variables, or equivalently to recognize positive threshold functions in polynomial time. However, the problem of recognizing when an arbitrary Boolean function is threshold is NP-complete. It is also shown that the list of maximal non-covers is essentially the most compact input possible, even if it is known in advance that the problem is regular.  相似文献   

15.
Pareto dominance is one of the most basic concepts in multi-objective optimization. However, it is inefficient when the number of objectives is large because in this case it leads to an unmanageable number of Pareto solutions. In order to solve this problem, a new concept of logic dominance is defined by considering the number of improved objectives and the quantity of improvement simultaneously, where probabilistic logic is applied to measure the quantity of improvement. Based on logic dominance, the corresponding logic nondominated solution is defined as a feasible solution which is not dominated by other ones based on this new relationship, and it is proved that each logic nondominated solution is also a Pareto solution. Essentially, logic dominance is an extension of Pareto dominance. Since there are already several extensions for Pareto dominance, some comparisons are given in terms of numerical examples, which indicates that logic dominance is more efficient. As an application of logic dominance, a house choice problem with five objectives is considered.  相似文献   

16.
A kind of chaotic synchronization method is presented in the paper. In the transmitter, part signals are transformed by wavelet and the detail information is removed. In the receiver, the component with low frequency is reconstructed and discrete feedback is used, we show that synchronization of two identical structure chaotic systems is attained. The effect of feedback on chaotic synchronization is discussed. Using the synchronous method, the transmitting signal is transported in compressible way, system resource is saved, the component with high frequency is filtered and the effect of disturbance on synchronization is reduced. The synchronization method is illustrated by numerical simulation experiment.  相似文献   

17.
In this paper, the problem of locating new facilities in a competitive environment is considered. The problem is formulated as the firm expected profit maximization and a set of nodes is selected in a graph representing the geographical zone. Profit depends on fixed and deterministic location costs and, since customers are independent decision-makers, on the expected market share. The problem is an instance of nonlinear integer programming, because the objective function is concave and submodular. Due to this complexity a branch & bound method is developed for solving small size problems (that is, when the number of nodes is less than 50), while a heuristic is necessary for larger problems. The branch & bound is called data-correcting method, while the approximate solutions are obtained using the heuristic-concentration method.  相似文献   

18.
This paper focuses on the density of the minimal subspaces generated by a class of discrete linear Hamiltonian systems. It is shown that the minimal subspace is densely defined if and only if the maximal subspace is an operator; that is, it is single valued. In addition, it is shown that, if the interval on which the systems are defined is bounded from below or above, then the minimal subspace is non-densely defined in any non-trivial case.  相似文献   

19.
沪深股市收益的相关性   总被引:4,自引:0,他引:4  
以概率作为相关度量指标,分整体相关性和尾部相关性对沪深两市收益进行考察。整体相关性采用概率方法中的变化协调形成的相关性作为度量,结果表明沪深两市收益在整体上具有一定的正相关性。对于尾部相关性,先用t分布分别拟事两市收益底分布,然后用蒙特卡洛模拟确定尾部的最优门限,进而求得尾部相关性,结果显示当市场剧烈波动时两市收益具有正的相关性,且比整体相关性强,尤其在暴跌的时候,两市具有很强的正相关性。  相似文献   

20.
油田注水系统拓扑布局优化的混合遗传算法   总被引:1,自引:0,他引:1  
以投资最小为目标函数,建立了注水系统拓扑布局优化数学模型.根据模型特点,将优化问题分为两层,分别采用遗传算法和非线性优化方法进行求解.并对遗传算法的操作过程进行了改进,调整了适应函数,改进了交叉和变异操作,结合了模拟退火算法,在操作过程中使约束条件得到满足,减少了不可行解的产生,使遗传算法的优化性能得到了提高.优化算例说明了该方法的有效性.  相似文献   

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