Published online by Cambridge University Press: 11 April 2024
A centre of a differential system in the plane $ {\mathbb {R}}^2$ is an equilibrium point $p$
 is an equilibrium point $p$ having a neighbourhood $U$
 having a neighbourhood $U$ such that $U\setminus \{p\}$
 such that $U\setminus \{p\}$ is filled with periodic orbits. A centre $p$
 is filled with periodic orbits. A centre $p$ is global when $ {\mathbb {R}}^2\setminus \{p\}$
 is global when $ {\mathbb {R}}^2\setminus \{p\}$ is filled with periodic orbits. In general, it is a difficult problem to distinguish the centres from the foci for a given class of differential systems, and also it is difficult to distinguish the global centres inside the centres. The goal of this paper is to classify the centres and the global centres of the following class of quintic polynomial differential systems
 is filled with periodic orbits. In general, it is a difficult problem to distinguish the centres from the foci for a given class of differential systems, and also it is difficult to distinguish the global centres inside the centres. The goal of this paper is to classify the centres and the global centres of the following class of quintic polynomial differential systems
 .
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ber das Auftreten von Wirbeln und Strudeln (geschlossener und spiraliger Integralkurven) in der Umgebung rationaler Unbestimmtheitsstellen. Math. Ann. 109 (1934), 395–424.CrossRefGoogle Scholar