Ekaterina Titova
Saint-Petersburg State Technological University of Plant Polymers,
197371, av. Koroleva 48/1-241,
SPb, Russia
The problem of robustness of invariant sets of periodic systems of ordinary differential equations is studied. The well-known result on persistence of hyperbolic invariant sets is generalized for the case then the linear part of the considered system is hyperbolic on a set of segments in the neighborhood of every solution, forming the invariant set.