Bautin’s theorem
There are at most three limit cycles which can appear in the following quadratic system
from a singular point, if its type is either a focus or a center.
In 1939 N.N. Bautin claimed the above result and in 1952 submitted the proof [BNN1]. [GAV]
References
- GAV Gaiko, A., Valery: Global Bifurcation Theory and Hilbert’s Sixteenth Problem. Kluwer Academic Publishers, London, 2003.
- BNN1 Bautin, N.N.: On the number of limit cycles appearing from an equilibrium point of the focus or center type under varying coefficients. Matem. SB., 30:181-196, 1952. (written in Russian)
- BNN2 Bautin, N.N.: On the number of limit cycles appearing from an equilibrium point of the focus or center type under varying coefficients. Translation
of the American Mathematical Society, 100, 1954.