Mawhin's continuation theorem of coincidence degree and integral inequality were used to construct a bounded open sets,and the non autonomous Lotka Volterra predator-prey system of three species with arbitrary time delay was discussedby giving a sufficient condition for the existence of the positive periodic solutionsin that if the coefficients satisfied certain conditions,periodic oscillationhas been obtained.%运用Mawhin重合度定理和积分不等式构造了有界开集，讨论了一类带任意多时滞的3种群非自治Lotka-Volterra竞争捕食系统，给出了正周期解存在的充分条件，在系数满足一定的条件时得到了周期振荡的结论。
展开▼
