报告题目：Rich dynamics in a delayed HTLV-I infection model
报告人：陈玉明教授 加拿大Wilfrid Laurier大学
内容摘要：In this joint work with Xuejun Pan and Professor Hongying Shu, we investigate the impact of time delay in CTL immune response on an HTLV-I infection model. We use the basic reproduction number for viral infection R0 and the basic reproduction number for CTL response RCTL to characterize the model dynamics. In particular, we obtain the global dynamics when R0 <1 or RCTL _ 1 < R0, as well as infection persistent result when R0 > 1. However, the model dynamics become very rich when RCTL > 1. In this case, we use the time delay as a bifurcation parameter to obtain stability switch result on the positive equilibrium and global bifurcation diagrams for the model system. We also conduct higher-order normal form analysis and apply center manifold theory to classify the rich model dynamics near double Hopf bifurcation points. Our analysis indicates that time delay in CTL immune response can induce not only Hopf bifurcation and double Hopf bifurcation, but also quasi-periodic orbits (torus) and coexistence of multiple stable periodic solutions.