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31.
The purpose of the present note is to provide a somewhat more flexible statement of the sufficiency conditions in Section 4 of Ref. 1 and to give explicit statements of the fundamental necessity and sufficiency results, which were only implicitly presented there. The additional flexibility is obtained by considering local, rather than global, pseudoconcavity requirements. 相似文献
32.
研究一类三阶非线性分布时滞动力方程的振动性,通过构造广义Riccati变换得到一类新的广义Riccati不等式,利用积分平均技巧等方法,建立了保证该方程一切解均振动或收敛于0的若干新的振动结果,推广和改进了近期文献的相关结论,并给出了若干例子。 相似文献
33.
研究了带非线性边界条件的二阶奇异微分系统边值问题- u ″ = Λ G ( t ) F ( u ) , 0 < t < 1 , u ( 0 ) = 0 , u ' ( 1 ) + C ( u ( 1 ) ) u ( 1 ) = 0 ![]()
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正解的存在性,其中u = ( u 1 , u 2 , ? , u n ) T , G ( t ) = d i a g [ g 1 ( t ) , g 2 ( t ) , ? , g n ( t ) ] , ![]()
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且g i ( t ) ![]()
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( i = 1,2 , ? , n ) ![]()
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在t = 0 ![]()
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处允许有奇性F ( u ) = ( f 1 ( u ) , f 2 ( u ) , ? , f n ( u ) ) T , C = d i a g ( c 1 , c 2 , ? , c n ) , ![]()
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Λ = d i a g ( λ 1 , λ 2 , ![]()
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? , λ n ) , ![]()
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λ i ![]()
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( i = 1,2 , ? , n ) 为 正 参 数 。 ![]()
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在非线性项F ![]()
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分别满足超线性、次线性和渐近线性的增长条件下,运用锥拉伸与压缩不动点定理获得了该问题正解的存在性结论。 相似文献
34.
A scheme for creating an arbitrary coherent superposition of two atomic states in serial multi-A-type system is proposed.This technique with the application of a control field is based on the existence of two degenerate dark states and their interaction.The mixing of the dark states can be controlled by changing the relative delay time of the control pulse.One can get any desired superposition by changing the delay time of the control pulse. 相似文献
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36.
对于2阶Duffing系统与3阶单模激光Lorenz系统,用主动控制方法设计了一种同步控制器,实现二者之间的缩阶反同步。依据罗斯 霍维兹判据,给出误差系统在原点处渐进稳定的条件。数值试验证实:在控制器作用下,2阶Duffing系统的状态变量与3阶单模激光Lorenz投影子系统的状态变量振动的幅值相同但方向相反,且在随机噪声干扰下反同步仍能很好地实现。这表明所设计的控制器对于不同阶的Duffing系统与Lorenz系统的缩阶反同步的实现是可行的、有效的,而且具有很好的鲁棒性。 相似文献
37.
Hai-Liang Li & Ling-Yun Shou 《数学研究通讯:英文版》2023,39(1):136-172
The one-dimensional compressible Navier-Stokes-Vlasov-Fokker-Planck system with density-dependent viscosity and drag force coefficients isinvestigated in the present paper. The existence, uniqueness, and regularityof global weak solution to the initial value problem for general initial data areestablished in spatial periodic domain. Moreover, the long time behavior ofthe weak solution is analyzed. It is shown that as the time grows, the distribution function of the particles converges to the global Maxwellian, and boththe fluid velocity and the macroscopic velocity of the particles converge to thesame speed. 相似文献
38.
It is well known that the classical Ascoli-Arzelà theorem is powerful technique to give a necessary and sufficient condition for investigating the relative compactness of a family of abstract continuous functions, while it is limited to finite compact interval. In this paper, we shall generalize the Ascoli-Arzelà theorem on an infinite interval. As its application, we investigate an initial value problem for fractional evolution equations on infinite interval in the sense of Hilfer type, which is a generalization of both Riemann-Liuoville and Caputo fractional derivatives. Our methods are based on the Hausdorff theorem, classical/generalized Ascoli-Arzelà theorem, Schauder fixed point theorem, Wright function, and Kuratowski measure of noncompactness. We obtain the existence of mild solutions on an infinite interval when the semigroup is compact as well as noncompact. 相似文献
39.
40.
In this paper, we address the impact of uncertainty introduced when the experts complete pairwise comparison matrices, in the context of multi-criteria decision making. We first discuss how uncertainty can be quantified and modeled and then show how the probability of rank reversal scales with the number of experts. We consider the impact of various aspects which may affect the estimation of probability of rank reversal in the context of pairwise comparisons, such as the uncertainty level, alternative preference scales and different weight estimation methods. We also consider the case where the comparisons are carried out in a fuzzy manner. It is shown that in most circumstances, augmenting the size of the expert group beyond 15 produces a small change in the probability of rank reversal. We next address the issue of how this probability can be estimated in practice, from information gathered simply from the comparison matrices of a single expert group. We propose and validate a scheme which yields an estimate for the probability of rank reversal and test the applicability of this scheme under various conditions. The framework discussed in the paper can allow decision makers to correctly choose the number of experts participating in a pairwise comparison and obtain an estimate of the credibility of the outcome. 相似文献