共查询到20条相似文献,搜索用时 718 毫秒
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引入了T_λ算子,基于此算子,对模糊集的凸和拟凸的一些性质进行了研究,得出了一些结论。对模糊集的凸和拟凸的概念进行了拓展,引入了半凸模糊集,半拟凸模糊集,研究了半凸模糊集和半拟凸模糊集的性质。 相似文献
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基于GRA-DEA模型的有关农民收入的九城市的评价 总被引:1,自引:0,他引:1
王有文 《数学的实践与认识》2018,(6)
有关农民收入,文章以山西省九个城市为例进行了评价.首先用灰色关联分析法分析了2016年这些城市的有关数据,筛选出影响农民收入的主要因素;其次构建了指标体系,利用数据包络分析法对有关农民收入九个城市进行了DEA有效性评价;再次对非DEA有效的城市,借助投影公式探索了改进方法;最后得出了九城市分为两类的结论,提出了针对性的建议. 相似文献
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由于自动控制理论提出了二阶微分方程的零解的全局稳定性,引起了不少数学工作者的研究,H.H.研究了方程组(1,1),得到了零解为全局稳定的充分条件,本文采用定性方法,研究了方程组(1,1)的零解为全局稳定的必要条件,并削弱了[1]中的充分条件,从而得到方程组(1,1)的零解为全局稳定的充要条件(定理 3——5).同时还研究了方程组(2,1)的零解为全局稳定的充要条件(定理6). 相似文献
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张肇濠 《数学的实践与认识》1979,(4)
本文在[1]的基础上,引进了递差方阵 D,给出了 Vandermonde 型阵 V_m 的逆阵的显示式,从而得到了方程组(1),(1′)的可供直接计算用的用三角阵表示的解的公式.此外,还得到了包括[2]的化(1′)为三角形方程组的结果. 相似文献
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混合单调半流与泛函微分方程的稳定性 总被引:6,自引:0,他引:6
本文首先提出混合单调半流的概念和泛函微分方程生成这种半流的条件。然后,利用半流的混合单调性,我们得到关于泛函微分方程的渐近稳定性和全局稳定性的新结果. 相似文献
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The aim of this paper is to obtain necessary and sufficient conditions for the existence of a nonuniform exponential dichotomy over a general class of linear skew-product semiflows (over semiflows) on a Banach space. We extend Datko’s classical result to the case of the exponential nonuniform dichotomy of linear skew-product semiflows over semiflows on a Banach space, by using Lyapunov norms. 相似文献
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Periodica Mathematica Hungarica - In this paper we consider individual stability for linear skew-product semiflows over semiflows by using the standard Perron’s method. To our knowledge, in... 相似文献
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This paper is concerned with a class of essentially strongly order-preserving semiflows, which are defined on an ordered metric space and are generalizations of strongly order-preserving semiflows. For essentially strongly order-preserving semiflows, we prove several principles, which are analogues of the nonordering principle for limit sets, the limit set dichtomy and the sequential limit set trichotomy for strongly order-preserving semiflows. Then, under certain compactness hypotheses, we obtain some results on convergence, quasiconvergence and stability in essentially strongly order-preserving semiflows. Finally, some applications are made to quasimonotone systems of delay differential equations and reaction-diffusion equations with delay, and the main advantages of our results over the classical ones are that we do not require the delicate choice of state space and the technical ignition assumption. 相似文献
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Nguyen Thieu Huy 《Journal of Mathematical Analysis and Applications》2007,333(2):731-752
In this paper we investigate the exponential dichotomy of linear skew-product semiflows over semiflows by considering the operators generated by the integral equation related to strongly continuous cocycles over metric spaces acting on Banach bundles. We characterize the existence of exponential dichotomy by properties of these operators and use this characterization to prove the robustness of exponential dichotomy. 相似文献
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Using the method of discretization, we investigate the necessary and sufficient conditions for the existence of exponential dichotomy of linear skew-product semiflows over semiflows through the existence of discrete exponential dichotomy of the discretized linear-skew product semiflows. We then apply the obtained results to consider the roughness of exponential dichotomy of linear-skew product semiflows. 相似文献
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In this paper we obtain necessary and sufficient conditions for uniform exponential instability of linear skew-product semiflows in terms of Banach sequence spaces and Banach function spaces, respectively. We deduce the versions of some theorems due to Datko, Neerven, Przyluski, Rolewicz and Zabczyk, for the case of instability of linear skew-product semiflows. 相似文献
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In this paper, we introduce a class of smooth essentially strongly order-preserving semiflows and improve the limit set dichotomy for essentially strongly order-preserving semiflows. Generic convergence and stability properties of this class of smooth essentially strongly order-preserving semiflows are then developed. We also establish the generalized Krein-Rutman Theorem for a compact and eventually essentially strongly positive linear operator. By applying the main results of this paper to essentially cooperative and irreducible systems of delay differential equations, we obtain some results on generic convergence and stability, the linearized stability of an equilibrium and the existence of the most unstable manifold in these systems. The obtained results improve some corresponding ones already known. 相似文献
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C. Stoica 《Journal of Mathematical Sciences》2009,161(2):327-336
The paper introduces the notion of skew-evolution semiflows and presents the concept of pointwise trichotomy in the case of
skew-evolution semiflows on a Banach space. The connection with the classical notion of trichotomy presented in [8] for evolution operators is also emphasized, and some characterizations are given. The approach of the theory is from a uniform
point of view. The study can also be extended to systems with control whose state evolution can be described by skew-evolution
semiflows.
Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 61, Optimal
Control, 2008. 相似文献
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Taishan Yi 《Journal of Differential Equations》2005,214(2):429-456
In this paper, we consider a class of pseudo monotone semiflows, which only enjoy some weak monotonicity properties and are defined on product-ordered topological spaces. Under certain conditions, several convergence principles are established for each precompact orbit of such a class of semiflows to tend to an equilibrium, which improve and extend some corresponding results already known. Some applications to delay differential equations are presented. 相似文献