In this paper the GL(2;R)-invariant center conditions for the origin of the coordinates of the phase plane of the cubic differential systems with degenerate infinity were established.
For the bidimensional polynomial systems of differential equations with nonlinearities of the fourth degree the recurent equations for determination of the Lyapunov quantities were established. Moreover, the general form ...
In this paper minimal rational bases of GL(2;R)-comitants and a rational basis of GL(2;R)-invariants for the bidimensional system of differential equations with nonlinearities of the fourth degree are presented.