一类 pitchfork 分支的全局相图

This paper deals with the following quadratic polynomial differential system ^dx_dt = y² − y − x, ^dy_dt = x² − µx − y, with parameter µ ∈ ℝ, which is the key example for studying the pitchfork bifurcation of a singular point. We classify the global phase portraits in the Poincaré disc of this system when µ varies.