应304am永利集团官网李万同教授与王智诚教授邀请，杭州师范大学徐衍聪教授将于2022年6月24日-6月26日与我校有关师生进行在线学术研讨，其中6月25日举行线上专题学术报告。

报告题目:Global Bifurcation analysis of an SIRS disease model with a convex incidence rate

时 间：6月25日下午14:40

腾讯会议ID：790 1862 7942 入会密码：123456

摘 要：In this paper, the global dynamics of an susceptible infectious recovered (SIRS) epidemic model with a generalized non-linear incidence function are investigated. It is shown that (1) not the basic reproduction number, but a sub-threshold value acts as a threshold value for the disease spread; (2) as parameters vary, the model exhibits saddle-node bifurcation, forward bifurcation, backward bifurcation, cusp type degenerate Bogdanov-Takens bifurcation of codimension 2 and 3, Hopf bifurcation, generalized Hopf bifurcation, homoclinic bifurcation, degenerate homoclinic bifurcation. Particularly, we find the existence of isolas of limit cycles, which tells us that two stable limit cycles and one unstable limit cycles coexist. We derive that the existence of codimension-three Bogdanov-Takens bifurcation as the organizing center of complex dynamics yields the bifurcation of homoclinic cycle and isola bifurcation of limit cycles, which provide the possible existence of three limit cycles. Actually, two limit cycles can emanate simultaneously from the isola center. Numerical simulations are presented to illustrate the theoretical results.

徐衍聪教授简介

徐衍聪，杭州师范大学数学系教授，博士生导师，系主任，美国（SIAM）工业与应用数学会员，美国数学评论评论员。目前主要从事动力系统分支理论、局部斑图分支及应用研究，主持国家自然科学基金面上项目各类基金10余项。

甘肃应用数学中心

甘肃省高校应用数学与复杂系统省级重点实验室

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萃英学院

2022年6月22日