The theory of algebraic invariants and comitants for polynomial autonomous systems of differential equations has been developed by C. Sibirschi and his disciples. One of the important problems concerning this theory is the ...

In this paper we consider the class of systems (1) (or (2)) with the conditions I3 = 0, I1 =0, I2 > 0. The conditions I1 = 0, I2 > 0 mean that the eigenvalues of the Jacobian matrix at the singular point (0, 0) are pure ...