Periodic points of the planar area preserving Poincaré map inside isolating segment

The aim of this note is to study the structure of the set of periodic points of the area preserving Poincaré map P associated to T-periodic local planar process. We will use the approach based on the method of periodic isolating segments (isolating chains) and the fixed point index theory. The number of the applications to the processes generated by periodic in time non-autonomous planar ODE's are given.