It is known that non-hyperbolic limit cycles are structurally unstable in the set of planar smooth and analytic vector fields. In the polynomial case, it is known only that limit cycles of even degree are structurally unstable. In this paper, we prove that non-hyperbolic limit cycles of odd degree are also structurally unstable in the polynomial case, if we consider Whitney's topology.
机构:
Sun Yat Sen Univ, Sch Math & Computat Sci, Dept Math, Guangzhou 510275, Guangdong, Peoples R ChinaSun Yat Sen Univ, Sch Math & Computat Sci, Dept Math, Guangzhou 510275, Guangdong, Peoples R China