Abel differential equations form a notable class of non-linear ordinary differential equations characterised by their polynomial non-linearities. These equations have been instrumental in exploring ...

A power series expansion in the damping parameter ε of the limit cycle U(t; ε) of the free van der Pol equation Ü + ε(U2-1) U̇ + U = 0 is constructed and analyzed. Coefficients in the expansion are ...

This paper presents a survey of results on the bifurcation of limit cycles from centers and separatrix cycles of perturbed planar analytic systems and contributes some new results on the bifurcation ...