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171.
R. XuF.A. Davidson M.A.J. Chaplain 《Journal of Mathematical Analysis and Applications》2002,269(1):256-277
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
172.
Shengqiang Liu Lansun ChenYoulin Jiang 《Journal of Mathematical Analysis and Applications》2002,271(1):124-138
In this paper, a two-species competitive model with stage structure is presented and studied. Results on the global extinction and permanence are given, which generalize the well-known three theorems for the two species competitive system and, moreover, they confirm the negative effect of stage structure on the permanence of populations as well as estimate the degree of such effect. Conclusions in this paper suggest that for a competitive community stage structure is also one of the important reasons that cause permanence and extinction. 相似文献
173.
Raúl Naulin 《Journal of Mathematical Analysis and Applications》2002,274(1):305-318
The unstable properties of the null solution of the nonautonomous delay system x′(t)=A(t)x(t)+B(t)x(t−r1(t))+f(t,x(t),x(t−r2(t))) are examined; the nonconstant delays r1, r2 are assumed to be continuous bounded functions. The case A=constant is reviewed, where a theorem, recalling the Perron instability theorem for ordinary differential equations, is obtained. 相似文献
174.
该文探讨了单支方法关于一类中立型延迟微分方程(NDDEs)系统的整体稳定性和渐近稳定性.在适当的条件下,获得了单支方法关于NDDEs系统的一些新的非线性稳定性判据. 相似文献
175.
得到了具有多重时滞非线性差分方程x(n 1)-x(n) ∑i=1^k pi(n)fi(x(gi(n)))=0,n=0,1,2,…的每个解趋于零的充分条件。 相似文献
176.
连续型随机序列与幂函数分布的比较及几何平均的若干强极限定理 总被引:1,自引:0,他引:1
本文引入似然比概念作为一般连续型随机变量相对于乘积幂函数分布的偏差的一种随机性度量 ,运用鞅理论及分析方法 [3 - 4 ] ,得到了一种新形式的强大数定理 ,即关于随机变量几何平均 Gn(ω)=∏ni=1Xi1 /n的强极限定理 . 相似文献
177.
本文应用上、下解方法和 Leray-Schauder不动点定理 ,证明了一类拟线性椭圆方程边值问题弱解的存在性 ,并且给出了一个应用实例 相似文献
178.
In this article, we study for the ‐realization of the vector‐valued Schrödinger operator . Using a noncommutative version of the Dore–Venni theorem due to Monniaux and Prüss, we prove that the ‐realization of , defined on the intersection of the natural domains of the differential and multiplication operators which form , generates a strongly continuous contraction semigroup on . We also study additional properties of the semigroup such as extension to L1, positivity, ultracontractivity and prove that the generator has compact resolvent. 相似文献
179.
Recent manipulations on vertebrates showed that the fear of preda-
tors, caused by prey after they perceived predation risk, could reduce the prey''s
reproduction greatly. And it''s known that predator-prey systems with fear ef-
fect exhibit very rich dynamics. On the other hand, incorporating the time
delay into predator-prey models could also induce instability and oscillations
via Hopf bifurcation. In this paper, we are interested in studying the com-
bined effects of the fear effect and time delay on the dynamics of the classic
Lotka-Volterra predator-prey model. It''s shown that the time delay can cause
the stable equilibrium to become unstable, while the fear effect has a stabi-
lizing effect on the equilibrium. In particular, the model loses stability when
the delay varies and then regains its stability when the fear effect is stronger.
At last, by using the normal form theory and center manifold argument, we
derive explicit formulas which determine the stability and direction of periodic
solutions bifurcating from Hopf bifurcation. Numerical simulations are carried
to explain the mathematical conclusions. 相似文献
180.
In order to investigate the impact of awareness programs and time delays on the cholera outbreaks, we propose a cholera epidemic model, incorporating awareness programs by media as a separate class and two time‐delay factors. The bifurcation theory is applied to explore the variety of dynamics of this model for various combinations of the delays when R0>1. Moreover, we analyze the direction, stability, and period of the bifurcating periodic solutions arising through Hopf bifurcation by using the normal form concept and the center manifold theory. Finally, we present numerical simulations to verify the main theoretical results. 相似文献