Electronic Journal of Differential Equations, Vol. 2012 (2012), No. 56, pp. 1-16. Title: Existence and topological structure of solution sets for phi-Laplacian impulsive differential equations Authors: Johnny Henderson (Baylor Univ., Waco, TX, USA) Abdelghani Ouahab (Sidi-Bel-Abbes Univ., Algeria) Samia Youcefi (Sidi-Bel-Abbes Univ., Algeria) Abstract: In this article, we present results on the existence and the topological structure of the solution set for initial-value problems for the first-order impulsive differential equation $$\displaylines{ (\phi(y'))' = f(t,y(t)), \quad\hbox{a.e. } t\in [0,b],\cr y(t^+_{k})-y(t^-_k)=I_{k}(y(t_{k}^{-})), \quad k=1,\dots,m,\cr y'(t^+_{k})-y'(t^-_k)=\bar I_{k}(y'(t_{k}^{-})), \quad k=1,\dots,m,\cr y(0)=A,\quad y'(0)=B, }$$ where $0=t_0