主讲人：李锋 临沂大学教授

时间：2022年6月18日14：30

地点：腾讯会议 241 673 194

举办单位：数理学院

主讲人介绍：李锋，临沂大学数学与统计学院教授，硕士生导师，美国《数学评论》评论员，韩国水原大学兼职博士生导师。2012年于中南大学数学与计算科学学院获理学博士学位。2014年，受国家留学基金资助，赴加拿大西大略大学访学一年。现主持国家自然科学基金面上项目1项。在Journal of Differential Equations, 中国科学、Nonlinear Analysis等杂志发表论文20余篇，2016年获山东省自然科学学术创新奖。

内容介绍：In this talk, bi-center and bi-isochronous center problems in cubic planar systems which are symmetric with respect to a straight line will be discussed. These systems can be transformed to ones which are symmetric with respect to the $y$-axis and have two symmetric singular points at $(\pm 1,0)$, which can be classified as elementary and nilpotent singular points. A complete classification is given on the centers, including nine conditions for elementary singular points and four conditions for nilpotent singular points. Moreover, six bi-isochronous center conditions are obtained for the elementary singular points.