Qualitative Theory of Dynamical Systems

, Volume 9, Issue 1–2, pp 319–324 | Cite as

Focal Values of Plane Cubic Centers

  • Hans-Christian Graf v. BothmerEmail author
  • Jakob Kröker
Open Access


We prove that the vanishing of 11 focal values is not sufficient to ensure that a complex plane cubic system has a complex center. This is done by finding a complex cubic system with a high order weak focus using an extensive computer search.


Tangent Space Formal Power Series Rational Polynomial Weighted Degree Convergent Power Series 
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Open Access

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Copyright information

© The Author(s) 2010

Authors and Affiliations

  1. 1.Courant Research Centre “Higher Order Structures”, Mathematisches InstitiutGeorg-August-Universität GöttingenGöttingenGermany

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