Periodic boundary value problem of functional differential equations with perturbation

By coincidence degree, the existence of solution to the periodic boundary value problem of functional differential equations with perturbation (formula presented) is proved, where x(t) ∈ Rn, xt ∈ BC(R, Rn) are given by xt(s) = x(t+s), b and G are continuous mappings from [0,T]×BC(R, Rn) into Rn and take bounded sets into bounded sets, b(t, ø) is linear with respect to ø∈ BC (R, Rn). Furthermore, a similar result to the periodic boundary value problem of functional differential equations with infinite delay is established. © 1999, Springer Verlag. All rights reserved.