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  • 天元讲堂(7.24)微分方程系列报告
  • 浏览量:349 发布人:佚名 发布时间:2017-07-21 11:22:45


  • 题目:Some problems in the unique normal form theory

     陈国廷 (法国里尔第一大学数学系主任)

    时间:7月24日 维格堂113   8:30-9:20

    摘要:我们将先介绍唯一正规型理论的一般方法. 然后讨论几个具体的正规型问题:

    平面幂零向量场, Hopf-zero向量场,带参数距阵的正规型.




    题目:Center of planar quasi-homogeneous polynomial differential systems

    于江(教授,上海交通大学)

    时间:7月24日 维格堂113   9:30-10:20

    摘要:In this paper, we characterize the centers of the quasi-homogeneous but non-homogeneous planar polynomial differential systems of any degree $n\in \mathbb N$. We prove that  systems do not admit centers if $n$ is even, and present the sufficient and necessary conditions that the systems admit a center if $n$ is odd. Furthermore, we provide an algorithm to obtain quasi-homogeneous but non-homogeneous systems with center for a given order. As an example, we characterize the center of the quasi-homogeneous but non-homogeneous of degree $7$.



    题目: Versal unfolding of planar systems at degenerate equilibria(I)(II)

     唐异垒(副教授,上海交通大学

    时间:7月24日 维格堂113  1);  10:30-11:20;  11:30-12:20

    摘要: In this talk we study bifurcations of a planar system  at a degenerate equilibrium, which has a zero linearization. We prove that such a degenerate system is of codimension 3 degeneracy in their classes. So  we introduce unfolding parameters to versally unfold the degenerate systems in the classes.  We display all bifurcations such as pitchfork bifurcation, saddle-center bifurcation and the Bogdanov-Takens bifurcati





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