摘要
<正> Suppose that the 2-dimensional systems of one-parameter equations of the form for α= 0 possess a continuous family {Γ~h} of periodic orbits in an annular region of the phase plane. The study of Poincaré bifurcations of(1)_α, namely, the creation of limit cycles from some closed orbits, may be confined to the investigation of how many zeros there are in the
基金
Project supported by the Science Fund of Academia Sinica
