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1.
A delayed three-species ratio-dependent predator-prey food-chain model without dominating in-stantaneous negative feedback is investigated. It is shown that the system is permanent under some appropriate conditions, and sufficient conditions are derived for the global attractivity of the positive equilibrium of the system.  相似文献   

2.
A delayed three-species ratio-dependent predator-prey food-chain model without dominating instantaneous negative feedback is investigated. It is shown that the system is permanent under some appropriate conditions, and sufficient conditions are obtained for the local asymptotic stability of a positive equilibrium of the system.  相似文献   

3.
A nonautonomous multispecies competition-predator system with type Ⅱfunctional response is studied in this paper. It is proved that the system is per-manent under some appropriate conditions. Further, if the system is a periodic one, a set of easily verifiable suflficient conditions which guarantee the existence, uniqueness and global attractivity of a strictly positive periodic solution are ob-tained.  相似文献   

4.
In this paper, we consider a nonautonomous competitive system which is also affected by toxic substances. Some averaged conditions for the permanence of this system are obtained. Our result shows that under some suitable assumption on the coefficients of the system, the toxic has no influence on the permanence of the system. Also, by using a suitable Lyapunov function, sufficient conditions which guarantee the attractivity of any two positive solutions of the system are obtained.  相似文献   

5.
This paper is concerned with the approximate controllability of nonlinear fractional impulsive neutral stochastic integro-differential equations with nonlocal conditions and infinite delay in Hilbert spaces under the assumptions that the corresponding linear system is approximately controllable. By the Krasnoselskii-Schaefer-type fixed point theorem and stochastic analysis theory, some sufficient conditions are given for the approximate controllability of the system. At the end, an example is given to illustrate the application of our result.  相似文献   

6.
In this paper, the definition of generalized isochronous center is given in order to study unitedly real isochronous center and linearizability of polynomial differential systems. An algorithm to compute generalized period constants is obtained, which is a good method to find the necessary conditions of generalized isochronous center for any rational resonance ratio. Its two linear recursive formulas are symbolic and easy to realize with computer algebraic system. The function of time-angle difference is introduced to prove the sufficient conditions. As the application, a class of real cubic Kolmogorov system is investigated and the generalized isochronous center conditions of the origin are obtained.  相似文献   

7.
For an inhomogeneous quasilinear hyperbolic system of diagonal form, under the assumptions that the system is linearly degenerate and the C^1 norm of the boundary data is bounded, we show that the mechanism of the formation of singularities of C^1 classical solution to the Goursat problem with C^1 compatibility conditions at the origin must be an ODE type. The similar result is also obtained for the weakly discontinuous solution with C^0 compatibility conditions at the origin.  相似文献   

8.
9.
A p-Laplacian system with Dirichlet boundary conditions is investigated. By the fibering method introduced by Pohozaev,we discuss the existence of positive weak solutions to the system under some proper conditions.  相似文献   

10.
Multivariate Hermite interpolation is widely applied in many fields, such as finite element construction, inverse engineering, CAD etc.. For arbitrarily given Hermite interpolation conditions, the typical method is to compute the vanishing ideal I (the set of polynomials satisfying all the homogeneous interpolation conditions are zero) and then use a complete residue system modulo I as the interpolation basis. Thus the interpolation problem can be converted into solving a linear equation system. A generic algorithm was presented in [18], which is a generalization of BM algorithm [22] and the complexity is O(τ^3) where r represents the number of the interpolation conditions. In this paper we derive a method to obtain the residue system directly from the relative position of the points and the corresponding derivative conditions (presented by lower sets) and then use fast GEPP to solve the linear system with O((τ + 3)τ^2) operations, where τ is the displacement-rank of the coefficient matrix. In the best case τ = 1 and in the worst case τ = [τ/n], where n is the number of variables.  相似文献   

11.
12.
具有反馈控制和功能反应的两种群竞争系统的解的渐近性   总被引:1,自引:0,他引:1  
讨论了具有反馈控制和功能反应的两种群竞争系统的解的渐近性质,获得了在一定条件下该种群持续生存的充分条件,以及该系统为周期系统时,存在全局渐近稳定的正周期解。  相似文献   

13.
A delayed Gause-type predator-prey system without dominating instantaneous negative feedbacks is investigated. It is proved that the system is uniformly persistent under some appropriate conditions. By means of constructing a suitable Lyapunov functional, sufficient conditions are derived for the local and global asymptotic stability of the positive equilibrium of the system.  相似文献   

14.
该文研究具有分布时滞和三个成长阶段的单种群模型,得到了系统永久持续生存的充分条件;同时通过构造Lyapunov 函数得到了系统全局渐近稳定的充分条件;最后建立具体模型说明所得结果的可行性.  相似文献   

15.
贾建文 《大学数学》2005,21(6):36-41
研究具有连续时滞和基于比率的非自治捕食扩散系统.证明了该系统一致持久性及任何正解全局渐近稳定性的充分条件.  相似文献   

16.
二次多项式微分系统的反射函数   总被引:1,自引:0,他引:1  
本文给出了二次多项式微分系统的反射函数的第一分量不依赖第二分量的充要条件,以及此时第二分量的表示式,及该系统存在周期解的条件。  相似文献   

17.
Given two hereditary dynamic systems having different dimensions, the conditions are provided under which a part of the motion of the larger system is reproduced by the smaller system, that is, the larger system “includes” the smaller one. The conditions for inclusion are useful in applying the concept of vector Liapunov functions to stability analysis of systems composed of overlapping subsystems. By expanding the systems into a larger space the overlapping subsystems appear as disjoint and standard methods can be used to conclude stability of the expanded system. Under the inclusion conditions, stability of the expansion implies stability of the original system. An example is provided to show stability where the standard disjoint decompositions fail.  相似文献   

18.
研究一类具有时滞和基于比率的三种群食物链捕食-被捕食动力学模型.证明了该系统在适当条件下的一致持久性;通过构造Lyapunov泛函,得到了该系统正平衡点全局渐近稳定的充分条件.  相似文献   

19.
A two-species ratio-dependent predator-prey model with distributed time delay is investigated. It is shown that the system is persistent under some appropriate conditions, and sufficient conditions are obtained for both the local and global stability of the positive equilibrium of the system.  相似文献   

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