Existence of solutions for nonlinear boundary value problems of impulsive differential equations

With the help of the coincidence degree continuation theorem, we generalize to the case of impulsive systems of the second order some existence results obtained by Gaines and Mawhin in the ordinary case. In particular, for the impulsive functions the treatment does not assume any monotonicity conditions, which are necessary in earlier papers treated by S.Hu and V.Lakshmikantham, L.H.Erbe and X.Liu with other methods.