DIFFERENTIAL EQUATION;
CRITICAL POINT;
EULER JACOBI FORMULA;
CENTER POINT;
D O I:
10.2307/2160021
中图分类号:
O29 [应用数学];
学科分类号:
070104 ;
摘要:
The Euler-Jacobi formula gives an algebraic relation between the critical points of a vector field and their indices. Using this formula we obtain an upper bound for the number of centers that a planar polynomial differential equation can have and study the distribution of the critical points for planar quadratic and cubic differential equations.