论文信息 - A method of constructing cycles without contact around a weak focus

A method of constructing cycles without contact around a weak focus

has a weak focus, then limit cycles can be made to appear in its neighborhood by varying slightly the right sides [ 11. Frommer [2], Bautin [3], Chin et al. [4], and Tung [5] are examples of excellent expositions of Poincare’s idea. It is necessary to go from numerical examples to general theory. In the first part of this paper, we present a method of constructing cycles without contact around a weak focus, which makes clear Poincart’s idea used in the above work [2-51. In the second part, another method to analyze global phase portraits is used. Quadratic systems with at least four limit cycles are produced by means of both the above methods, this contradicts the results of Petrovskii and Landis [6].

Shi Songling | Shi Songling | Songling Shi

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