【学术讲座】Complex bifurcations and new types of structure uncovered in the Qi system
报告题目：Complex bifurcations and new types of structure uncovered in the Qi system
报告人：李先义二级教授（浙江科技大学）
时间：2025年6月30日上午10:00-11:30
地点：四川轻化工大学宜宾校区A6-110
报告人简介：
李先义，博士，二级教授，博导，浙江省“钱江学者”特聘教授，浙江科技大学“科大学者”特聘教授；华东师范大学本、硕、博，法国里尔科技大学博士后；现为浙江科技大学非线性分析研究所所长。发表科研论文130余篇，其中SCI收录80余篇，主持国家自然科学基金等各级各类科研项目20余项；先后被评为“湖南省青年骨干教师”、“湖南省新世纪‘121’人才工程”人选、“湖南省学科带头人”、 “广东省‘千百十’人才工程省级培养对象”等；获“湖南省高校科技工作先进工作者”“上海市研究生优秀成果”（优博）、全国第三届“秦元勋常微分方程奖”等科研奖励与荣誉近20项。
报告内容简介：
In this talk, we revisit the Qi system and reveal its previously undiscovered complex dynamical characteristics. We first rigorously characterize the precise distribution of its equilibria in its total parameter space, then completely analyze the stability of all of its equilibria. Next, what's more important, we investigate its bifurcation problems concerning both the quantity of equilibria and stability boundaries, further analyzing codimension-two bifurcations between subcritical and supercritical pitchfork bifurcations as well as codimension-three Hopf bifurcations. Finally, through numerical encoding of system trajectory, we generate biparametric sweep that unveils several remarkable phenomena deserving deeper exploration, where, most significantly, we first in the Qi system discover intriguing and new structures: self-similar UII-shaped structure and shrimp-shaped structure.
