© 2018, Springer Science+Business Media, LLC, part of Springer Nature. For planar polynomial vector fields of the form (-y+X(x,y))∂∂x+(x+Y(x,y))∂∂y,where X and Y start at least with terms of second order in the variables x and y, we determine necessary and sufficient conditions under which the origin is a center or a uniform isochronous centers.
- Center-focus problem
- Polynomial planar differential system
- Uniform isochronous centers