一类n+2次生态系统的极限环

Limit Cycle of a Class of n+2-degree Ecosystem

本文研究一类n+2次生态系统:ddxt=x(a0+a1x-a2x2-a3yn-a4xyn)-H0,dydt=y(bx2-d).利用常微分方程定性理论进行分析,得到了该系统极限环存在与不存在的充分条件.

A class of n＋ 2-degree Ecosystem dx/dt=x（a0＋a1x-a2x^2-a3y^n-a4xy^n）-H0,dy/dt=y（bx^2-d） Is studied in this paper. The sufficient conditions of nonexistence and existence of limit cycle of the system are abtained.