中文摘要：

对已经获得的关于具有周期系数的两种群多时滞Lotka-volterra系统正周期解的存在性和稳定性结果进行了归纳总结.在上述研究中,借助Mawhin拓扑度方法和Liapunov函数技巧,分别建立了竞争系统,捕食系统和互惠系统正周期解存在且全局吸引的充分条件,发现这些条件能够与对应的自治系统正平衡点的存在性和稳定性条件较好的对应起来,而且发现时滞对系统的渐近行为是有影响的.

英文摘要：

In this paper, we make a summary of some results on the existence and global attractivity of positive periodic solutions of a multi - delayed two - species Lotka - voherra system including competitire, predator- prey and facuhative forms. In the above research, by using Mawhin＇s continuous theorem and liapunov function, sufficient conditions for the existence and global attractivity of positive periodic solutions of the above three systems are derived, respectively. These results show that they can formally correspond to that of positive equilibrium of autonomous undelayed systems, respectively. Moreover, these results indicate that the periodic delays have effect on the asymptotic behaviors of systems.