%0 Journal Article %T Periodic solutions for nonautonomous differential equations and inclusions in tubes %A Grzegorz Gabor %J Abstract and Applied Analysis %D 2004 %I Hindawi Publishing Corporation %R 10.1155/s1085337504403042 %X We study the existence of periodic trajectories for nonautonomous differential equations and inclusions remaining in a prescribed compact subset of an extended phase space. These sets of constraints are nonconvex right-continuous tubes not satisfying the viability tangential condition on the whole boundary. We find sufficient conditions for existence of viable periodic trajectories studying properties of the exit subset of the tube. A new approximation approach for continuous multivalued maps is presented. %U http://www.hindawi.com/journals/aaa/2004/235082/abs/