Two-dimentional systems $\dot x=P(x,y), \dot y=Q(x,y)$, where $P$ and $Q$ are real holomorphic functions, $2\pi$-periodic on $x$, which have integrating factor $\mu(x,y)$ are studied. The structure of limit cycles of the first and the second genus was investigated as well as singular limit cycles in the form of separatrix of the simple saddle. The analytic struture of Darbouxian integrating factor $\mu(x,y)$ for such systems was found.
Main publications:
Moulcot A. Integrating factors and limit cycles of dynamical systems with the cylindrical phase space // Proceedings of Int. Conference "Progress in Nonlinear Science", July 2–6, 2001, p. 65–55.
