In this paper,a predator prey system with time delay and Gompertz growth rate is investigated.By analyzing the associated characteristic equation of the system,the local stability of the positive equilibrium and the existence of Hopf bifurcations are established.Based on the normal form theory and center manifold reduction,explicit formulae are derived which determine the stability and direction of the bifurcating periodic solutions.%研究一类具有时滞和Gompertz增长率的捕食系统,通过分析系统的特征方程,得到正平衡点的局部稳定性和系统出现Hopf分支的条件,并利用中心流形定理和规范型理论,得到确定Hopf分支方向和分支周期解稳定性的计算公式.
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