Phase portraits of planar semi-homogeneous vector fields. III (Q1936517)

The authors consider the semi-homogeneous planar system \[ \begin{aligned} {dx\over dt} &= ax+ by,\\ {dy\over dt} &= Ax^4+ Bx^3y+ Cx^2 y^2+ Dxy^3+ Ey^4.\end{aligned} \] They prove that the phase portrait of any such system having finitely many equilibria is topologically equivalent to one of the 180 configurations described in the paper. The paper continues the studies of the authors in [Nonlinear Anal., Theory Methods Appl. 39, No. 3, A, 351--363 (2000; Zbl 0944.34022); ibid. 29, No. 7, 783--811 (1997; Zbl 0886.34026)].