StatusThe thesis was presented on the 23 February, 2007
Approved by NCAA on the 19 April, 2007
Abstract– 0.39 Mb / in romanian
1.21 Mb /
The thesis is devoted to the study of quadratic differential systems
dx/dt= a00 + a10x + a01y + a20x² + 2a11xy + a02y²=P(x; y);
dy/dt= b00 + b10x + b01y + b20x² + 2b11xy + b02y²=Q(x; y) (1)
with real coefficients.
The goal of the thesis is to determine the affine-invariant conditions for the existence of centers of symmetry on the phase plane of the systems (1), and to investigate these systems.
The main results obtained in the thesis are the following: