Hu, Xiaoling; Zheng, Longfei; Yan, Jurang The existence of positive periodic solutions of a time-lag predator-prey system with functional response. (Chinese. English summary) Zbl 1150.92341 J. North Univ. China, Nat. Sci. 27, No. 2, 97-99 (2006). Summary: An investigation has been made of a time-lag predator-prey system with functional response by using the continuation theorem in coincidence degree theory, obtaining sufficient conditions for identifying the existence of positive periodic solutions to the ecosystem. The findings in this paper have improved and generalized some of the viewpoints in the literature. MSC: 92D40 Ecology 34C25 Periodic solutions to ordinary differential equations 34K13 Periodic solutions to functional-differential equations Keywords:coincidence degree PDFBibTeX XMLCite \textit{X. Hu} et al., J. North Univ. China, Nat. Sci. 27, No. 2, 97--99 (2006; Zbl 1150.92341)