2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/66381The classical Center-Focus problem posed by H. Poincare in 1880's asks about the classification of planar polynomial vector fields such that all their integral trajectories are closed curves whose interiors contain a fixed point (which is called a center). In this paper we describe a new general approach to the Center Problem.one more part is addedComplex Variables34C07; 32E20; 58K10text