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1.
In this paper, we prove a theorem on the growth of a solution of a linear differential equation. From this we obtain some uniqueness theorems concerning that a nonconstant entire function and its derivatives sharing a small entire function. The results in this paper improve many known results. Some examples are provided to show that the results in this paper are the best possible.  相似文献   

2.
发展流动与形成流动   总被引:2,自引:0,他引:2  
本文着重研究振荡状态下的管流问题.从基本的Navier-Stokes方程出发,进行线性化之后采用虚宗量Bessel函数的方法求解,得出了一组描述圆管振荡状态下发展流动的速度分布、压力分布公式.它们较之Atabek等人推导的公式更为简明和易于计算.并且,在相同的条件下简化为形成流动的表达式后,两者的公式完全一致.数值计算还表明,本文公式的理论结果无论是和Atabek等人的理论计算结果比较,还是和他们的实验结果比较,都是相当一致的.  相似文献   

3.
本文用变厚度板壳大挠度理论的修正迭代法[1],对周边固定,在复合载荷下的变厚度圆薄板进行了求解,从而得到了精确度较高的二次近似解析解.将本文的结果退化到特殊情况就可以得到和文[1、2]完全一致的结果.本文还绘出特征曲线进行比较,其结果是理想的.  相似文献   

4.
We prove a theorem on the growth of nonconstant solutions of a linear differential equation. From this we obtain some uniqueness theorems concerning that a nonconstant entire function and its linear differential polynomial share a small entire function. The results in this paper improve many known results. Some examples are provided to show that the results in this paper are the best possible.  相似文献   

5.
In this paper, we study the growth of solutions of a first-order linear differential equation and that of a second-order linear differential equation. From this we obtain some uniqueness theorems of a nonconstant entire function and its first derivative having the same fixed points with the same multiplicities. The results in this paper also improve some known results. Some examples show that the results in this paper are best possible.  相似文献   

6.
研究了具时变时滞的分层抑制细胞神经网络.利用不动点定理获得了若干判定该网络存在概周期解的新充分条件,改进和推广了已有文献中的相应结论.  相似文献   

7.
通过利用Banach 空间中的不动点定理和Lyapunov泛函的方法,获得了时滞细胞神经网络概周期解的存在性与全局指数稳定性的新结论. 所获结果在较大程度上改进和推广了已有文献中的相应结果.  相似文献   

8.
B-空间上凸函数的若干指数性质   总被引:1,自引:0,他引:1  
周金海 《应用数学》2000,13(2):90-94
本文引入且用次梯度集该划Banach空间上凸函数的上、下指数,得到共轭凸函数上、下指数间的完整共轭关系、正齐次凸函数是Minkovski规函数的幂等结果,已有的一维相关结果是本文的特例。  相似文献   

9.
1992 年, 杨乐和王跃飞在有穷级条件下给出了亚纯函数具有满亏量和的充分必要条件, 并解决了1976 年Drasin 提出的三个著名问题. 本文在超级有穷条件下证明了杨乐和王跃飞的相应结果也成立, 从而在超级有穷条件下解决了Drasin 提出的三个著名问题, 改进了杨乐和王跃飞的相应结果, 并举例说明本文结果在某种意义上是最佳的.  相似文献   

10.
Ramsey数的性质研究   总被引:2,自引:0,他引:2  
宋恩民 《应用数学》1994,7(2):216-221
本文得出了若干有关Ramsey数性质的结论,这些结论可直接用来推导Ram-sey数的下界公式,也可用来改进已有的Ramsey数的下界结果,本文中定理的证明思路,还能用于研究其它的图论和组合数学问题。  相似文献   

11.
In this paper, some new results about the existence of positive solutions for singular semi-positone boundary value problems are obtained. The results of this paper partially improve the former corresponding work.  相似文献   

12.
In this paper,Chebyshev pseudospectral-finite element schemes are proposed for solving three dimensional vorticity equation.Some approximation results in nonisotropic Sobolev spaces are given.The generalized stability and the convergence are proved strictly.The numerical results show the advantages of this method.The technique in this paper is also applicable to other three-dimensional nonlinear problems in fluid dynamics.  相似文献   

13.
研究一类具有混合时滞的中立型Hopfield神经网络概周期解.通过运用指数二分性及不动点定理,获得了其概周期解的存在性与全局指数稳定性的充分条件,所得结果是新的,并且推广和改进了已有文献的相关结果.  相似文献   

14.
研究一致凸Banach空间中集值渐近拟非扩张映射的关于有限步迭代序列逼近公共不动点的充分必要条件,并在此条件下,证明了该序列收敛到公共不动点的一些强收敛定理,所得结果是单值映射情形的推广和发展.  相似文献   

15.
利用鞅收敛定理讨论马氏环境中马氏链的强收敛性,建立相应的强大数定律,使得已知的一系列结果为其特例.  相似文献   

16.
In this paper, weak and strong convergence theorems of the modified Noor iterations with errors are established for asymptotically nonexpansive mappings in Banach spaces. The results obtained in this paper extend and improve the several recent results in this area.  相似文献   

17.
本文在很弱的条件下得到了关于无约束最优化的Polak—Ribiere和Hestenes-Stiefel共轭梯度法的全局收敛性的新结果,这里 PR方法和HS方法中的参数β_k~(PR)和β_k~HS可以在某个负的区域内取值,这一负的区域与k有关.这些新的收敛性结果改进了文献中已有的结果.数值检验的结果表明了本文中新的 PR方法和 HS方法是相当有效的.  相似文献   

18.
In this paper the shunting inhibitory cellular neural networks (SICNNs) with time-varying delays are considered. Without assuming the global Lipschitz and bounded conditions of activation functions, sufficient conditions for the existence of the almost periodic solutions are established by using a fixed point theorem. The results of this paper are new and complement previously known results.  相似文献   

19.
In this paper, the new subclass Bn( ,a,A,B) of analytic functions is introduced. Its subordination relations, inclusion relations, the inequality properties and convering theorem are discussed. The results obtained in this paper are sharp, which generalize the related works of some authors and some other new results are obtained.  相似文献   

20.
By Lyapunov functional method, sufficient conditions for the asymptotic stability of a class of neutral-type systems are discussed in this paper. This work extends some results on the stability of neutral-type systems in the previous papers. Several numerical examples are listed in the end of this paper to confirm our results.  相似文献   

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